High quality and ultra large screen liquid crystal display device and production method thereof

ABSTRACT

A large screen liquid crystal display device using a transverse electric field system which is capable of dramatically improving an aperture ratio, a transmittance ratio, brightness, and contrast with low cost and high production yield. For example, the width of the common electrodes that shield the electric fields of the video signal lines can be decreased dramatically and the aperture ratio can be improved dramatically. Especially, the bumps covering the video signal lines can be used along with the spacers, and with the use of halftone exposure method, the bumps covering the video signal lines and the spacers can be constructed at the same time, which dramatically shortens the time required for the production process.

FIELD OF THE INVENTION

This invention relates to a liquid crystal display device using atransverse electric field system, and more particularly, to an ultralarge screen liquid crystal display device which is capable ofdramatically improving an aperture ratio, a transmittance ratio,brightness, and contrast with low cost and high production yield.

BACKGROUND OF THE INVENTION

A liquid crystal display device utilizing a transverse electric fieldsystem which applies an electric field to a liquid crystal in a paralleldirection with a substrate has a wide viewing angle and is the standardfor a large screen liquid crystal display. Such technologies have beenproposed, for example, by Japanese patent laid-open publication Nos.10-55000, 10-325961, 11-24104, 10-55001, 10-170939, and 11-52420, andhave been improved to solve problems such as vertical crosstalk.

Numerous technologies have been proposed by liquid crystal makersincluding a technology in which a photolithography spacer is utilized toimprove the contrast of a transverse electric field type liquid crystaldisplay system. For example, such a technology has been proposed byJapanese patent laid-open publication Nos. 2000-199904 and 2000-19527.The majority of them utilize a photolithography technology to establisha spacer on a color filter substrate. The Japanese patent laid-openpublication Nos. 2000-19527 and 2000-199904 show an idea of producing anelectric field of a video signal line in a vertical direction of asubstrate rather than a horizontal direction in order to suppress thevertical crosstalk. This requires the dielectric constant of thephotolithography spacer to be larger than the dielectric constant of theliquid crystal. The Japanese patent laid-open publication No. 2000-19526also proposed a photolithography spacer in which the dielectric constantis larger than that of the liquid crystal.

The Japanese patent laid-open publication No. 2001-209053 proposes aphotolithography spacer in a vertical electric field system utilizingdielectric material with a smaller dielectric constant than that of theliquid crystal along a video signal line to cover the video signal linein order to lower the waveform distortion. According to this patentpublication, the liquid crystal cell is constructed by creating a vacuumspace inside the liquid crystal cell, then injecting the liquid crystalin the space through an injection opening using the atmosphericpressure. In this liquid crystal injection method, a batch process isused in which several hundred cells are processed at the same time toproduce a large liquid crystal panel.

Japanese patent laid-open publication Nos. 2002-258321 and 2002-323706teach a structure using a dielectric material of a smaller dielectricconstant than that of the liquid crystal along the video signal line tocover the video signal line and placing a transparent conductivematerial along the video signal line to improve the pixel aperture ratioas well as to prevent signal delay.

FIG. 3 is a flow chart showing a typical production process in theconventional technology for producing a TFT (thin film transistor) arraysubstrate (active matrix substrate) of the transverse electric fieldtype liquid crystal panel. This production process includes four-stepphotomasking processes using the conventional halftone exposuretechnology. FIGS. 36A-36F are cross sectional views showing thestructural developments in accordance with the production flow of FIG. 3using the four-step photomasking technology.

In the conventional production process of FIG. 3, gate electrodes ofthin film transistors and common electrodes are formed at the same timein step S11. Then, at step S12, thin film transistors are separated froma semiconductor layer and source electrodes and drain electrodes of thethin film transistors are formed using the halftone photomask exposure.In step S13, contact holes for gate terminals, data terminals, pixeldrain portions, and transistor circuits for electrostatic protection arecreated. Then, at step S14, gate terminals, data terminals, transparentconductive pixel electrodes are formed.

In the cross sectional views of FIGS. 36A-36F, a numeral 6 denotes anarea on a positive photoresist layer after development where UV exposureis blocked, a numeral 7 denotes an area on the positive photoresistlayer after development where the UV exposure is made through thehalftone (translucent) photomask, a numeral 9 denotes a gate insulationfilm, a numeral 10 denotes a thin film semiconductor layer (non-dopedlayer), a numeral 11 denotes a thin film semiconductor layer (dopedlayer, i.e., ohmic contact layer), a numeral 15 denotes a scanning line,a numeral 50 denotes a scanning line terminal, a numeral 51 denotes avideo signal line, a numeral 54 denotes a scanning line drive circuitcontact electrode, a numeral 64 denotes a drain electrode of the thinfilm transistor, and a numeral 65 denotes a transparent pixel electrode.

Prior to the start of the processes of FIGS. 36A-36F, the scanning lines15 and the scanning terminals 50 are formed on a glass substrate (notshown). In FIG. 36A, the gate insulation film 9, the thin filmsemiconductor layer (non-doped layer) 10 and the thin film transistorohmic contact layer 11 are respectively deposited by, for example, a CVDplasma device. The positive photoresist 6 is coated and the halftoneexposure is conducted so that the thicker positive photoresist 6 and thethinner positive photoresist 7 are created. In FIGS. 36B and 36C,through a dry etching process, the thin film transistors are separatedfrom the semiconductor layer. In FIG. 36D, the drain electrode 64 of thethin film transistor and the video signal line 51 are formed by furtherconducting the etching process. In FIG. 36E, through the dry etching,contact holes are created over the scanning line terminals 50. In FIG.36F, the scanning line drive circuit electrodes 54 and the transparentpixel electrodes 65 are formed.

The conventional transverse electric field type liquid crystal panelutilizes common electrodes placed at both sides of the video signal lineto shield the electric field caused by the signal video line. In orderfor this construction to completely solve the problem involved with thevertical crosstalk, it is necessary to design the width of the commonelectrodes to be at least 1.5 times larger than that of the video signalline, hence resulted in a reduction of the pixel aperture ratio.

It is possible to reduce the vertical crosstalk by collecting theelectric force lines of the electric field produced by the video signalline to the photolithography spacer. This can be done by placing a blackmask made of thin film conductive material (chromium oxide layer andchromium metal thin film layer) at the side of color filter and settingthe electric potential of the black mask to that of the commonelectrodes, and creating a photolithography spacer that is placed in anelongated fashion at the same direction as the video signal line by aninsulation material that has a dielectric constant larger than that ofthe liquid crystal. However, in this method, because the material oflarge dielectric constant is used, the capacitance between the blackmask and the video signal line is increased, hence the video signalwaveform is delayed and distorted, which is not appropriate for a largescreen liquid crystal panel.

As disclosed in Japanese patent laid-open publication No. 11-24104, itis possible to almost completely shield the video signal line byconstructing a passivation layer on the video signal line and placing ashielding electrode thereon along the video signal line. However,because this construction utilizes a very thin passivation layer with athickness in the range between 0.3 micrometer and 1 micrometer, and thepassivation layer made of silicon oxide or silicon nitride has arelatively large dielectric constant of 4-6, the capacitance between theshielding electrode and the video signal line increases. This causes thesignal waveform to be delayed and distorted and is not appropriate for alarge screen liquid crystal display panel.

Japanese patent laid-open publication No. 2001-209053 discloses aphotolithography spacer constructed in a very thin manner that surroundthe video signal line using a dielectric material of a small dielectricconstant so that the capacitance between the common electrodes on theside of the color filter and the video signal line can be decreased.This technology, however, utilizes a conventional method of injectingthe liquid crystal through an injection opening. Thus, the thin and longphotolithography spacers cause the liquid crystal to be injected at avery slow speed, which severely decreases the production efficiency.

Japanese patent laid-open publication Nos. 2002-258321 and 2002-323706disclose a structure which utilizes a dielectric material that has asmaller dielectric constant than that of the liquid crystal to cover thevideo signal line and places a transparent conductive material along thevideo signal line so that the pixel aperture ratio can be improved andthe video signal line delay can be prevented. However, with thisconstruction, it is not possible to produce the liquid crystal cell andthe spacer at the same time. Therefore, an additional photolithographyprocess has to be performed to produce the photolithography spacers.This causes the production processes to be more complicated and costly.

The implementation of the technology disclosed in Japanese patentlaid-open publication No. 2002-258321 is not enough to produce atransverse electric field type liquid crystal panel with high contrastand low light leakage. When an angle of the bumps of the dielectricmaterial with a small dielectric constant that cover the video signallines along the video signal lines is larger than 40 degrees, theconventional technology of rubbing treatment using rubbing cloth causesareas with alignment defects due to the sideways slip caused at thetapered portions of the bumps in the direction of the movement at thetips of hairs of the rubbing cloth or areas on the inclined surfaces ofthe bumps where the hair tips of the rubbing cloth cannot reach.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above mentionedproblems involved in the conventional technology, and it is an object ofthe present invention to provide a large screen color liquid crystaldisplay device which is capable of achieving an improved aperture ratio,a transmittance ratio, high brightness and high contrast while promotinglow cost and high production yield.

In order to achieve the above objectives, in the first aspect of thepresent invention, a thin and long bump made of insulation material isplaced on a video signal line formed on a transverse electric field typeactive matrix substrate in a manner to cover the video signal line.Then, a common electrode is formed along the video signal line in amanner to cover the thin and long insulation bump and the video signalline, thereby shielding an electric field generated by the video signalline.

In the second aspect of the present invention, a thin and long bump madeof insulation material is placed on a video signal line formed on atransverse electric field type active matrix substrate in a manner tocover the video signal line. Then, a common electrode is formed on bothside walls of the thin and long insulation bump in a manner to sandwichthe video signal line, thereby shielding an electric field generated bythe video signal line.

In the third aspect of the present invention, the thin and longinsulation bump formed in the manner to cover the video signal line, inthe first and the second aspects of the present invention noted above,is used as a spacer to define a liquid crystal cell gap when assemblingthe liquid crystal cells.

In the fourth aspect of the present invention, a thin and long bump madeof insulation material for covering the video signal line on thetransverse electric field type active matrix substrate and a spacer todefine a liquid crystal cell gap are formed at the same time through ahalftone exposure process. Then, a common electrode is formed on thethin and long insulation bump in a manner to cover the video signalline, thereby shielding an electric field generated by the video signalline.

In the fifth aspect of the present invention, a thin and long bump madeof insulation material for covering the video signal line on thetransverse electric field type active matrix substrate and a spacer todefine a liquid crystal cell gap are formed at the same time through ahalftone exposure process. Then, a common electrode is formed on bothside walls of the thin and long insulation bump in a manner to sandwichthe video signal line, thereby shielding an electric field generated bythe video signal.

In the sixth aspect of the present invention, the common electrode forshielding the video signal line, in the first, second, third, fourth andfifth aspects of the present invention noted above, is made of athin-film transparent conductive material that allows the light totransmit in a degree greater than 20% such as titanium metal compoundincluding titanium nitride (TiNx), titanium oxide nitride (TiOxNy),titanium silicide nitride (TiSixNy), and titanium silicide (TiSix), or ametal oxide transparent conductive material such as indium oxide (In2O3)or zinc oxide (ZnO).

In the seventh aspect of the present invention, the thin and longinsulation bump formed in the manner to cover the video signal line, inthe first, second, third, fourth and fifth aspects of the presentinvention noted above, has a cross sectional shape of circular,semi-circular, hyperbolic, or parabolic shape and a taper angle θ of theinsulation bump is 30 degrees or less.

In the eighth aspect of the present invention, the thin and longinsulation bump formed in the manner to cover the video signal line, inthe first, second, third, fourth and fifth aspects of the presentinvention noted above, is not formed around an area at which the videosignal line and the scanning line intersect with one another.

In the ninth aspect of the present invention, the spacer that isconstructed at the same time as the thin and long insulation bump usingthe halftone exposure process, in the fourth and fifth aspects of thepresent invention noted above, is not covered by the common electrode atan area around the top thereof so as to expose the dielectric materialthat forming the spacer.

In the tenth aspect of the present invention, the spacer that defines aheight of the thin and long insulation bump and the gap of the liquidcrystal cell, in the fourth and fifth aspects of the present inventionnoted above, has a height difference h2 within a range between 0.2micrometers and 2.0 micrometers.

In the eleventh aspect of the present invention, a density of thespacers that are constructed at the same time with the thin and longinsulation bumps through the halftone exposure process, in the fourthand fifth aspects of the present invention noted above, is in a rangebetween one (1) and seventy five (75) per square millimeter and thespacers are distributed evenly throughout the substrate.

In the twelfth aspect of the present invention, an area of the spacerthat is constructed at the same time with the thin and long insulationbump through the halftone exposure process, in the fourth and fifthaspects of the present invention noted above, is in a range between 200square micrometers and 2000 square micrometers per one squaremillimeter.

In the thirteenth aspect of the present invention, a thin and long bumpmade of insulation material is formed on a video signal line formed on atransverse electric field type active matrix substrate in a manner tocover the video signal line. Then, a common electrode is formed alongthe video signal line in a manner to cover the thin and long insulationbump and the video signal line, thereby shielding the electric fieldgenerated by the video signal line. Further, a thin and long insulationbump is similarly formed on a scanning line in a manner to cover thescanning line. Then, a common electrode is formed on side walls of thescanning line in a manner to sandwich the scanning line, therebyshielding the electric field generated by the scanning line.

In the fourteenth aspect of the present invention, a thin and long bumpmade of insulation material is formed on a video signal line formed on atransverse electric field type active matrix substrate in a manner tocover the video signal line. Then, a common electrode is formed on bothside walls of the thin and long insulation bump in a manner to sandwichthe video signal line, thereby shielding the electric field generated bythe video signal line. Further, a thin and long insulation bump issimilarly formed on a scanning line in a manner to cover the scanningline. Then, a common electrode is formed on both side walls of thescanning line in a manner to sandwich the scanning line, therebyshielding the electric field generated by the scanning line.

In the fifteenth aspect of the present invention, the thin and longinsulation bumps formed in the manner to cover around the video signalline and the scanning line, in the thirteenth and fourteenth aspects ofthe present invention noted above, are used as a spacer to define aliquid crystal cell gap when assembling the liquid crystal cells.

In the sixteenth aspect of the present invention, a thin and long bumpmade of insulation material for covering the video signal line on thetransverse electric field type active matrix substrate and a spacer todefine a liquid crystal cell gap are formed at the same time through ahalftone exposure process. Then, a common electrode is formed on thethin and long insulation bump in a manner to cover the video signalline, thereby shielding the electric field generated by the video signalline. Further, a thin and long insulation bump is similarly formed on ascanning line through a halftone exposure process in a manner to coverthe scanning line. Then, a common electrode is formed on both side wallsof the scanning line in a manner to sandwich the scanning line, therebyshielding the electric field generated by the scanning line.

In the seventeenth aspect of the present invention, a thin and long bumpmade of insulation material for covering the video signal line on thetransverse electric field type active matrix substrate and a spacer todefine a liquid crystal cell gap are formed at the same time through ahalftone exposure process. Then, a common electrode is formed on bothside walls of the thin and long insulation bump in a manner to sandwichthe video signal line, thereby shielding the electric field generated bythe video signal. Further, a thin and long insulation bump is similarlyformed on a scanning line through a halftone exposure process in amanner to cover the scanning line. Then, a common electrode is formed onboth side walls of the scanning line in a manner to sandwich thescanning line, thereby shielding the electric field generated by thescanning line.

In the eighteenth aspect of the present invention, the common electrodesfor shielding the video signal line and the scanning line, in thethirteenth, fourteenth, fifteenth, sixteenth and seventeenth aspects ofthe present invention noted above, are made of thin-film transparentconductive material that allows the light transmit in a degree greaterthan 20% such as titanium metal compound including titanium nitride(TiNx), titanium oxide nitride (TiOxNy), titanium silicide nitride(TiSixNy), and titanium silicide (TiSix), or a metal oxide transparentconductive material such as indium oxide (In 2O3) or zinc oxide (ZnO).

In the nineteenth aspect of the present invention, the thin and longinsulation bumps formed in the manner to cover the video signal line andthe scanning line, in the thirteenth, fourteenth, fifteenth, sixteenthand seventeenth aspects of the present invention noted above have, havea cross sectional shape of circular, semi-circular, hyperbolic, orparabolic shape and a taper angle θ of the insulation bump is 30 degreesor less.

In the twentieth aspect of the present invention, the thin and longinsulation bumps formed in the manner to cover the video signal line andthe scanning line, in the thirteenth, fourteenth, fifteenth, sixteenthand seventeenth aspects of the present invention noted above, are notformed around an area at which the video signal line and the scanningline intersect with one another.

In the twenty first aspect of the present invention, the spacer that isconstructed at the same time as the thin and long insulation bumpthrough the halftone exposure process, in the sixteenth and seventeenthaspects of the present invention noted above, is not covered by thecommon electrode at an area around the top thereof so as to expose thedielectric material that forming the spacer.

In the twenty second aspect of the present invention, the spacer thatdefines a height of the thin and long insulation bump and a gap of theliquid crystal cell, in the sixteenth and seventeenth aspects of thepresent invention noted above, has a height difference h2 within a rangebetween 0.2 micrometers and 2.0 micrometers.

In the twenty third aspect of the present invention, a density of thespacers that are constructed at the same time with the thin and longinsulation bump through the halftone exposure process, in the sixteenthand seventeenth aspects of the present invention noted above, is in arange between one (1) and seventy five (75) per square millimeter andthe spacers are distributed evenly throughout the substrate.

In the twenty fourth aspect of the present invention, an area of thespacer that is constructed at the same time with the thin and longinsulation bump through the halftone exposure process, in the sixteenthand seventeenth aspects of the present invention noted above, is in arange between 200 square micrometers and 2000 square micrometer per onesquare millimeter.

In the twenty fifth aspect of the present invention, the commonelectrodes, in the first, second, third, fourth, fifth, thirteenth,fourteenth, fifteenth, sixteenth and seventeenth aspects of the presentinvention noted above, are provided in an upper layer and a lower layerthrough a gate insulating film and a passivation film therebetween in amanner to sandwich the video signal line in up/down directions andright/left directions wherein the common electrode on the lower layer ismade of a metal electrode which prohibits the light to pass therethrough whereas the common electrode in the upper layer is a transparentelectrode that allows the light to pass there through. The commonelectrode at the upper layer has an electrode width wider than that ofthe common electrode in the lower layer and is projected towards theside of the liquid crystal drive electrode.

In the twenty sixth aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, and the common electrode formed along the videosignal line for shielding the video signal line, in the first, second,third, fourth, fifth, thirteenth, fourteenth, fifteenth, sixteenth andseventeenth aspects of the present invention noted above, are aligned ina manner of straight line wherein the liquid crystal drive electrodewithin the pixel and the common electrode within the pixel are bentwithin the pixel at least once at an angle within a range between 0-30degrees (except 0 degree) relative to an alignment direction of theliquid crystal molecule.

In the twenty seventh aspect of the present invention, the video signalline and the thin and long insulation bump formed in the manner to coverthe video signal line, in the first, second, third, fourth, fifth,thirteenth, fourteenth, fifteenth, sixteenth and seventeenth aspects ofthe present invention noted above, are aligned in a manner of straightline wherein the common electrode formed along the video signal line forshielding the video signal line, the liquid crystal drive electrodewithin the pixel, and the common electrode within the pixel are bentwithin the pixel at least once at an angle within a range between 0-30degrees (except 0 degree) relative to an alignment direction of theliquid crystal molecule.

In the twenty eighth aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, the common electrode formed along the videosignal line for shielding the video signal line, and the commonelectrode within the pixel, in the first, second, third, fourth, fifth,thirteenth, fourteenth, fifteenth, sixteenth and seventeenth aspects ofthe present invention noted above, are aligned in a manner of straightline wherein only the liquid crystal drive electrode within the pixel isbent within the pixel at least once at an angle within a range between0-30 degrees (except 0 degree) relative to an alignment direction of theliquid crystal molecule.

In the twenty ninth aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, the common electrode formed along the videosignal line for shielding the video signal line, the common electrodewithin a pixel, and the liquid crystal drive electrode within the pixel,in the first, second, third, fourth, fifth, thirteenth, fourteenth,fifteenth, sixteenth and seventeenth aspects of the present inventionnoted above, are bent within the pixel at least once at an angle withina range between 0-30 degrees (except 0 degree) relative to an alignmentdirection of the liquid crystal molecule.

In the thirtieth aspect of the present invention, the video signal line,the thin and long insulation bump formed in the manner to cover thevideo signal line, the common electrode formed along the video signalline for shielding the video signal line, the common electrode withinthe pixel, and the liquid crystal drive electrode within the pixel, inthe first, second, third, fourth, fifth, thirteenth, fourteenth,fifteenth, sixteenth and seventeenth aspects of the present inventionnoted above, are bent within the pixel at least once at an angle withina range between 0-30 degrees (except 0 degree) relative to an alignmentdirection of the liquid crystal molecule, and similarly, the colorfilter layer and the light shielding film (black mask) on the side ofthe color filter substrate which is opposite to the active matrixsubstrate are bent within the pixel at least once at an angle within arange between 0-30 degrees (except 0 degree) relative to an alignmentdirection of the liquid crystal molecule.

In the thirty first aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, and the common electrode formed along the videosignal line for shielding the video signal line, in the first, second,third, fourth, fifth, thirteenth, fourteenth, fifteenth, sixteenth andseventeenth aspects of the present invention noted above, are aligned ina manner of straight line wherein the liquid crystal drive electrodewithin the pixel and the common electrode within the pixel are bentwithin the pixel at least once at an angle within a range between 60-120degrees (except 90 degrees) relative to an alignment direction of theliquid crystal molecule.

In the thirty second aspect of the present invention, the video signalline and the thin and long insulation bump formed in the manner to coverthe video signal line, in the first, second, third, fourth, fifth,thirteenth, fourteenth, fifteenth, sixteenth and seventeenth aspects ofthe present invention noted above, are aligned in a manner of straightline wherein the common electrode formed along the video signal line forshielding the video signal line, the liquid crystal drive electrodewithin the pixel, and the common electrode within the pixel are bentwithin the pixel at least once at an angle within a range between 60-120degrees (except 90 degrees) relative to an alignment direction of theliquid crystal molecule.

In the thirty third aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, the common electrode formed along the videosignal line for shielding the video signal line, and the commonelectrode within the pixel, in the first, second, third, fourth, fifth,thirteenth, fourteenth, fifteenth, sixteenth and seventeenth aspects ofthe present invention noted above, are aligned in a manner of straightline wherein only the liquid crystal drive electrode within the pixel isbent within the pixel at least once at an angle within a range between60-120 degrees (except 90 degrees) relative to an alignment direction ofthe liquid crystal molecule.

In the thirty fourth aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, the common electrode formed along the videosignal line for shielding the video signal line, the common electrodewithin the pixel, and the liquid crystal drive electrode within thepixel, in the first, second, third, fourth, fifth, thirteenth,fourteenth, fifteenth, sixteenth and seventeenth aspects of the presentinvention noted above, are bent within the pixel at least once at anangle within a range between 60-120 degrees (except 90 degrees) relativeto an alignment direction of the liquid crystal molecule.

In the thirty fifth aspect of the present invention, the video signalline, the thin and long insulation bump formed in the manner to coverthe video signal line, the common electrode formed along the videosignal line for shielding the video signal line, the common electrodewithin the pixel, and the liquid crystal drive electrode within thepixel, in the first, second, third, fourth, fifth, thirteenth,fourteenth, fifteenth, sixteenth and seventeenth aspects of the presentinvention noted above, are bent within the pixel at least once at anangle within a range between 60-120 degrees (except 90 degrees) relativeto an alignment direction of the liquid crystal molecule, and similarly,the color filter layer and the light shielding film (black mask) on theside of the color filter substrate which is opposite to the activematrix substrate are bent within the pixel at least once at an anglewithin a range between 60-120 degrees (except 90 degrees) relative to analignment direction of the liquid crystal molecule.

In the thirty sixth aspect of the present invention, the thin and longinsulation bump formed along the video signal line to cover the videosignal line, in the first, second, third, fourth, fifth, thirteenth,fourteenth, fifteenth, sixteenth and seventeenth aspects of the presentinvention noted above, has a dielectric constant of less than 3.3, and aheight h1 is in a range between 1.5 micrometers and 5.0 micrometers. Adistance L1 between an edge of the video signal line and an edge of theinsulation bump is in a range between 3.0 micrometers and 6.0micrometers.

In the thirty seventh aspect of the present invention, a distance L2between an edge of the insulation bump covering the video signal lineand an edge of the shielding common electrode covering the insulationbump, in the first, second, third, fourth, fifth, thirteenth,fourteenth, fifteenth, sixteenth and seventeenth aspects of the presentinvention noted above, is in a range between 0.5 micrometers and 10.0micrometers.

In the thirty eighth aspect of the present invention, monomer oroligomer used as a material for fabricating the insulation bump coveringthe video signal line, in the first, second, third, fourth, fifth,thirteenth, fourteenth, fifteenth, sixteenth and seventeenth aspects ofthe present invention noted above, has at least one benzo-cyclobutenestructure or its dielectric form or has at least one fluorene skeletonor its dielectric form.

In the thirty ninth aspect of the present invention, when forming thethin and long insulation bump covering the video signal line, in thefirst, second, third, fourth, fifth, thirteenth, fourteenth, fifteenth,sixteenth and seventeenth aspects of the present invention noted above,at least one barrier bump spacer in a closed loop structure is formed atthe same time for preventing the breakage of a main seal due to anatmospheric pressure or a pressure from liquid crystals at a locationidentical to an area on which the main seal of the liquid crystal cellthat surrounds an entire effective pixel area is formed.

In the fortieth aspect of the present invention, a process of producingan active matrix substrate of a transverse electric field type activematrix liquid crystal display device is conducted in the followingsteps:

-   -   (1) forming patterns for scanning lines (scanning line        patterning step);    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island step);    -   (3) forming the video signal lines and the liquid crystal drive        electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the insulation bumps        that cover the video signal lines at the same time (halftone        exposure process);    -   (5) forming the contact holes for terminal portions and for the        static electricity protection circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal line and the transparent common electrodes within        the pixel at the same time.

In the forty first aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines, common electrodes within the        pixels, and lower layer common electrodes for shielding the        video signal lines at the same time;    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island step);    -   (3) forming the video signal lines and the liquid crystal drive        electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the insulation bumps        that cover the video signal lines at the same time (halftone        exposure process);    -   (5) forming the contact holes for terminal portions and for the        static electricity protection circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal lines.

In the forty second aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming patterns for the scanning lines;    -   (2) forming the patterns of etching stopper channels for the        thin film transistors;    -   (3) forming the video signal lines and the liquid crystal drive        electrode at the same time;    -   (4) forming the spacer bumps that cover the video signal line,        or simultaneously forming the spacers and the insulation bumps        that cover the video signal lines at the same time (halftone        exposure process);    -   (5) forming the contact holes for terminal portions and for the        static electricity protection circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal lines and the transparent common electrodes within        the pixels at the same time.

In the forty third aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines, common electrodes within the        pixels, and the lower layer common electrodes for shielding the        video signal lines at the same time;    -   (2) forming the patterns of etching stopper channels for the        thin film transistors;    -   (3) forming the video signal lines and the liquid crystal drive        electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the insulation bumps        that cover the video signal lines at the same time (halftone        exposure process);    -   (5) forming the contact holes for terminal portions and for the        static electricity protection circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal lines.

In the forty fourth aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the patterns for the scanning lines;    -   (2) forming the video signal lines and the liquid crystal drive        electrodes, and separating silicon elements for the thin film        transistors from the semiconductor layer at the same time        (halftone exposure process);    -   (3) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the insulation bumps        that cover the video signal lines at the same time (halftone        exposure process);    -   (4) forming the contact holes for terminal portions and for the        static electricity protection circuits; and    -   (5) forming the transparent common electrodes for shielding the        video signal lines and the transparent common electrodes within        the pixels at the same time.

In the forty fifth aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines, the common electrodes within the        pixels, and the lower layer common electrodes for shielding the        video signal lines at the same time;    -   (2) forming the video signal lines and the liquid crystal drive        electrodes, and separating silicon elements for the thin film        transistors from the semiconductor layer at the same time        (halftone exposure process);    -   (3) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the insulation bumps        that cover the video signal lines at the same time (halftone        exposure process);    -   (4) forming the contact holes for terminal portions and for the        static electricity protection circuits; and    -   (5) forming the transparent common electrodes for shielding the        video signal lines.

In the forty sixth aspect of the present invention, the commonelectrodes formed along the thin and long insulation bumps in the mannerto surround the video signal lines for shielding, in the first, second,third, fourth, fifth, thirteenth, fourteenth, fifteenth, sixteenth andseventeenth aspects of the present invention noted above, are connectedwith each other throughout the entire effective pixel display area andare set to an electric potential close to a center voltage of the videosignal voltage.

In the forty seventh aspect of the present invention, the electrode forone pixel for driving the liquid crystal molecule, in the first, second,third, fourth, fifth, thirteenth, fourteenth, fifteenth, sixteenth andseventeenth aspects of the present invention noted above, is configuredby three different electrodes including a single electrode connected tothe thin film transistor for driving the liquid crystal, a lower layercommon electrode formed both right and left sides of the pixel forshielding the video signal line, and an upper layer shielding commonelectrode formed along the thin and long insulation bump surrounding thevideo signal line, so that there exist no common electrodes within thepixel.

In the transverse electric field type active matrix liquid crystaldisplay device in the forty eighth aspect of the present invention,processes for planarizing (leveling) the active matrix substrate andconstruction of the photolithography spacers are conducted at the sametime by first applying negative photoresist with a thickness which is asum of a liquid crystal cell gap and the largest thickness among thecommon electrode within the pixel made of non-transparent metal materialor metal silicide or metal nitride, the lower layer common electrode forshielding the video signal line, and the liquid crystal drive electrode,then exposing the ultraviolet light to the entire effective pixel areafrom the back surface of the active matrix substrate, and thencompletely exposing the ultraviolet light to the portions where thespacers are formed using the photomask for the photolithography spacers,and lastly developing the active matrix substrate.

In the forty ninth aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors), common electrodes within the pixels, and lower        layer common electrodes for shielding the video signal lines at        the same time;    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island);    -   (3) forming the video signal lines and the liquid crystal drive        electrodes at the same time;    -   (4) forming the contact holes for terminal portions and for the        static electricity protection circuits;    -   (5) forming the scanning line terminal portions, the video        signal line terminal portions, and the static electricity        protection circuits at the same time; and    -   (6) forming the photolithography spacers and leveling the        effective pixel area (halftone back surface exposure process).

In the fiftieth aspect of the present invention, a process of producingan active matrix substrate of a transverse electric field type activematrix liquid crystal display device is conducted in the followingsteps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors), the common electrodes within the pixels, and the        lower layer common electrodes for shielding the video signal        lines at the same time;    -   (2) forming the patterns of etching stopper channels for the        thin film transistors;    -   (3) forming the video signal lines and the liquid crystal drive        electrodes at the same time;    -   (4) forming the contact holes for the terminal portions and for        the static electricity protection circuits;    -   (5) forming the scanning line terminal portions, the video        signal line terminal portions, and the static electricity        protection circuits at the same time; and    -   (6) forming the photolithography spacers and leveling the        effective pixel area (halftone back surface exposure process).

In the fifty first aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors), the common electrodes within the pixels, and the        lower layer common electrodes for shielding the video signal        lines at the same time;    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island);    -   (3) forming the contact holes for the terminal portions and for        the static electricity protection circuits;    -   (4) forming the video signal lines, the liquid crystal drive        electrodes, the scanning line terminal portions, the video        signal line terminal portions, and the static electricity        protection circuits at the same time; and    -   (5) forming the photolithography spacers and leveling the        effective pixel area (halftone back surface exposure process).

In the fifty second aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors), the common electrodes within the pixels, and the        lower layer common electrodes for shielding the video signal        lines at the same time; and    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island) and        forming the contact holes for the terminal portions and for the        static electricity protection circuits (first and second        halftone exposure processes).

In the fifty third aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors), the common electrodes within the pixels, and the        lower layer common electrodes for shielding the video signal        lines at the same time;    -   (2) forming the video signal lines and the liquid crystal drive        electrodes and separating the silicon elements for the thin film        transistors from the semiconductor layer at the same time        (halftone exposure process);    -   (3) forming the contact holes for the terminal portions and for        the static electricity protection circuits;    -   (4) forming the scanning line terminal portions, the video        signal line terminal portions, and the static electricity        protection circuits at the same time; and    -   (5) forming the photolithography spacers and leveling the        effective pixel area (halftone back surface exposure process).

In the fifty fourth aspect of the present invention, a process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors), the common electrodes within the pixels, and the        lower layer common electrodes for shielding the video signal        lines at the same time (using a masking deposition process        incorporating a shadow frame for a structure of P—SiNx\a-Si i        layer\n+a-Si layer);    -   (2) forming the video signal lines, the liquid crystal drive        electrodes, the static electricity protection circuits, and the        scanning line terminal portions, and separating the silicon        elements for the thin film transistors from a semiconductor        layer at the same time (halftone exposure process); and    -   (3) forming the photolithography spacers and leveling the        effective pixel area (halftone back surface exposure process).

In the fifty fifth aspect of the present invention, with respect to thehalftone back surface exposure apparatus that is used in the leveling(planarization) process for the effective pixel area of the activematrix substrate of the transverse electric field type liquid crystaldisplay device, silica optical fiber cables for ultraviolet light orultraviolet light LED are bundled in an in-line form in such a way thatthe ultraviolet rays can expose only the effective pixel area of theactive matrix substrate of the transverse electric field type liquidcrystal display device from the back side of the substrate.

In the fifty sixth aspect of the present invention, with respect to thehalftone back surface exposure process, in the forty eighth, fortyninth, fiftieth, fifty first, fifty second, fifty third and fifty fourthaspects of the present invention noted above, the entire effective pixelarea is exposed by the ultraviolet light from the back surface of theactive matrix substrate before completely exposing the ultraviolet lighton the portions where the spacers are to be constructed by using aphotomask for photolithography spacer construction. Then, after thedevelopment of the substrate, degrees of irregularity of the substratesurface within the effective pixel area at side of the active matrixsubstrate and the heights of the spacers are measured with use of awhite light interferometer so that the coating thickness of thephotoresist and the amount of light for the halftone back surfaceexposure are controlled in response to the measured data from the whitelight interferometer through a feedback control process.

In the fifty seventh aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted in thefollowing steps:

-   -   (1) forming the alignment marks inside of a glass substrate with        use of a laser beam;    -   (2) depositing two or more layers of different kinds of metals        or metal compounds or alloys (portions where the alignment marks        are created by the laser beam are not deposited);    -   (3) exposing the gate bus lines and the common bus lines after        the application of positive photoresist through the first        halftone exposure process of an under exposure method that        utilizes an ordinary photomask, then, the gate bus line, the        common bus line, the common electrodes for shielding the video        signal lines, and the common electrodes within the pixels are        exposed through the second exposure process;    -   (4) after the development, the deposited metals are etched away        with use of a first wet etching or dry etching process, then,        removing the positive photoresist at the areas of the halftone        exposure by an oxygen plasma ashing method, and then removing        the metal layers at the halftone exposed area that are        unnecessary through a second dry etching or wet etching process,        and forming the gate bus, common bus, common electrodes for        shielding the video signal lines, and the common electrodes        within the pixels by using the first and second etching        processes;    -   (5) depositing the gate insulation film, a non-doped thin film        semiconductor layer (a-Si i layer), and a n+a-Si layer (ohmic        contact layer) and coating the positive photoresist thereon,        then exposing the a-Si silicon islands through a first halftone        exposure process of an under exposure method with use of a        normal photomask, and then exposing the contact holes for gate        terminal connection portions and for the static electricity        protection circuits through a second exposure process;    -   (6) after the development, forming the contact holes for the        gate terminal connection portions and the static electricity        protection circuits by etching away the gate insulation film,        non-doped thin film semiconductor layer (a-Si i layer), and the        n+a-Si layer (ohmic contact layer) through a first dry etching        process, then, after removing the positive photoresist at the        area of the halftone exposure with use of an oxygen plasma        ashing method, removing the non-doped thin film semiconductor        layer (a-Si i layer) and the n+a-Si layer (ohmic contact layer)        that are unnecessary at the halftone exposed area with use of a        second dry etching process, and then, constructing the a-Si        silicon islands, the gate terminal connection portions, and the        static electricity protection circuit with use of the first and        second etching processes; and    -   (7) constructing the video signal lines, the liquid crystal        drive electrodes, the static electricity protection circuits,        and the gate terminals at the same time (through the halftone        exposure process using the normal photomask).

In the fifty eighth aspect of the present invention, an exposure deviceused in the production process for producing the thin film transistorsof the active matrix display device of the present invention has afunction of performing a second halftone exposure (complete exposure)process after shifting the active matrix substrate in a horizontaldirection for the length of about a half of the channel length of thethin film transistor after performing a first halftone exposure(incomplete exposure) process using a normal photomask to construct thesource electrodes and the drain electrodes of a channel length of abouta half of the channel length of the thin film transistor.

In the fifty ninth aspect of the present invention, the process ofproducing the thin film transistors of the active matrix liquid crystaldisplay device is conducted by, first performing the first halftoneexposure (incomplete exposure; under exposure) with use of a normalphotomask to construct the source electrodes and the drain electrodes ofthe thin film transistors with the channel length of about a half of thechannel length of the thin film transistor, then, shifting the activematrix substrate in a horizontal direction for the length of about ahalf of the target channel length of the thin film transistor, and thendeveloping the positive photoresist after performing the second halftoneexposure (incomplete exposure; under exposure), thereby reducing thethickness of the positive photoresist of the channel portion of the thinfilm transistor by an amount corresponding to the target channel length.

In the sixtieth aspect of the present invention, the halftone shiftexposure technology in the fifty ninth aspect of the present inventionnoted above is used for performing the silicon element separation forthe thin film transistors, and the formation of the video signal lines(source electrodes) and the drain electrodes (electrodes connected tothe liquid crystal drive electrodes or the transparent pixel electrodes)at the same time.

In the sixty first aspect of the present invention, the process ofproducing the active matrix substrate is conducted with use of thehalftone shift exposure technology in the fifty ninth aspect of thepresent invention noted above by the following steps:

-   -   (1) forming the scanning lines (gate electrodes of the thin film        transistors) and the common electrodes at the same time;    -   (2) forming the video signal lines (source electrodes of the        thin film transistors) and the drain electrodes, and separating        the silicon element for the thin film transistors from a        semiconductor layer at the same time (halftone exposure        process);    -   (3) forming the contact holes for the scanning line terminal        portions, the video signal line terminal portions, and for the        static electricity protection circuits; and    -   (4) forming the scanning line terminal portions, the video        signal line terminal portions, the static electricity protection        circuits, and transparent electrodes at the same time.

In the sixty second aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted with use of thehalftone shift exposure technology in the fifty ninth aspect of thepresent invention noted above by the following steps:

-   -   (1) forming the scanning lines (gate electrodes), the common        electrodes within the pixels, and the lower layer common        electrodes for shielding the video signal lines at the same time        (using a masking deposition process incorporating a shadow frame        in the case of using the structure of P—SiNx\a-Si i layer\n+a-Si        layer);    -   (2) forming the video signal lines, the liquid crystal drive        electrodes, the static electricity protection circuits, and the        scanning line terminal portions, and separating the silicon        elements for the thin film transistors from the semiconductor        layer at the same time (halftone exposure process); and    -   (3) forming the photolithography spacers and leveling the        effective pixel area (halftone back surface exposure process).

In the sixty third aspect of the present invention, the spacer bumps, inthe third, fourth, fifth, fifteenth, sixteenth, and seventeenth aspectsof the present invention noted above, have a characteristic ofelastically and evenly deforming along the entire effective pixel areain a range between 0.1 micrometers and 0.5 micrometers in response tothe atmospheric pressure during the construction of the liquid crystalcell by superposing the active matrix substrate and the color filtersubstrate with one another under a vacuum atmosphere.

In the sixty fourth aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted by thefollowing steps:

-   -   (1) forming the scanning lines;    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island step);    -   (3) forming the video signal lines (source electrodes) and the        drain electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the bumps that cover        the video signal lines (halftone exposure process);    -   (5) forming the contact holes for the terminal portions, the        drain electrodes, and the static electricity protection        circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal line, the transparent common electrodes within the        pixels, and the liquid crystal drive electrodes at the same        time.

In the sixty fifth aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted by thefollowing steps:

-   -   (1) forming the scanning lines and the lower layer common        electrodes for shielding the video signal lines at the same        time;    -   (2) separating the silicon elements for the thin film        transistors from the semiconductor layer (silicon island step);    -   (3) forming the video signal lines (source electrodes) and the        drain electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the bumps that cover        the video signal lines (halftone exposure process);    -   (5) forming the contact holes for the terminal portions, the        drain electrodes, and the static electricity protection        circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal lines, the transparent common electrodes within the        pixels, and the liquid crystal drive electrodes at the same        time.

In the sixty sixth aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted by thefollowing steps:

-   -   (1) forming the scanning lines;    -   (2) forming the patterns of etching stopper channels for the        thin film transistors;    -   (3) forming the video signal lines (source electrodes) and the        drain electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the bumps that cover        the video signal lines (halftone exposure process);    -   (5) forming the contact holes for terminal portions, drain        electrodes, and static electricity protection circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal lines, the transparent common electrodes within the        pixels, and the liquid crystal drive electrodes at the same        time.

In the sixty seventh aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted by thefollowing steps:

-   -   (1) forming the scanning lines and the lower layer common        electrodes for shielding the video signal lines at the same        time;    -   (2) forming the patterns of etching stopper channels for the        thin film transistors;    -   (3) forming the video signal lines (source electrodes) and the        drain electrodes at the same time;    -   (4) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the bumps that cover        the video signal lines (halftone exposure process);    -   (5) forming the contact holes for the terminal portions, the        drain electrodes, and the static electricity protection        circuits; and    -   (6) forming the transparent common electrodes for shielding the        video signal lines, the transparent common electrodes within the        pixels, and the liquid crystal drive electrodes at the same        time.

In the sixty eighth aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted by thefollowing steps:

-   -   (1) forming the scanning lines;    -   (2) forming the video signal lines (source electrodes) and the        drain electrodes, and separating the silicon elements for the        thin film transistors from the semiconductor layer at the same        time (halftone exposure process);    -   (3) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the bumps that cover        the video signal lines (halftone exposure process);    -   (4) forming the contact holes for the terminal portions, the        drain electrodes, and the static electricity protection        circuits; and    -   (5) forming the transparent common electrodes for shielding the        video signal lines, the transparent common electrodes within the        pixels, and the liquid crystal drive electrodes at the same        time.

In the sixty ninth aspect of the present invention, the process ofproducing an active matrix substrate of a transverse electric field typeactive matrix liquid crystal display device is conducted by thefollowing steps:

-   -   (1) forming the scanning lines and the lower layer common        electrodes for shielding the video signal lines at the same        time;    -   (2) forming the video signal lines (source electrodes) and the        drain electrodes, and separating silicon elements for the thin        film transistors from the semiconductor layer at the same time        (halftone exposure process);    -   (3) forming the spacer bumps that cover the video signal lines,        or simultaneously forming the spacers and the bumps that cover        the video signal lines (halftone exposure process);    -   (4) forming the contact holes for the terminal portions, the        drain electrodes, and the static electricity protection        circuits; and    -   (5) forming the transparent common electrodes for shielding the        video signal lines, the transparent common electrodes within the        pixels, and the liquid crystal drive electrodes at the same        time.

In the seventieth aspect of the present invention, the video signalline, the thin and long insulation bumps formed in the manner to coverthe video signal lines, the upper layer common electrodes for shieldingthe electric fields caused by the video signal lines, the lower layercommon electrodes for shielding, and the liquid crystal drive electrodeswithin the pixels in the forty seventh aspect of the present inventionnoted above are bent within the pixel at least once at an angle within arange between 0-30 degrees (except 0 degree) relative to an alignmentdirection of the liquid crystal molecule, and similarly, the colorfilter layer and the light shielding film (black mask) on the side ofthe color filter substrate which is opposite to the active matrixsubstrate are bent within the pixel at least once at an angle within arange between 0-30 degrees (except 0 degree) relative to the alignmentdirection of the liquid crystal molecule.

In the seventy first aspect of the present invention, the video signalline, the thin and long insulation bumps formed in the manner to coverthe video signal lines, the upper layer common electrodes for shieldingthe electric fields caused by the video signal lines, the lower layercommon electrodes for shielding, and the liquid crystal drive electrodeswithin the pixels in the forty seventh aspect of the present inventionnoted above are bent within the pixel at least once at an angle within arange between 60-120 degrees (except 90 degrees) relative to analignment direction of the liquid crystal molecule, and similarly, thecolor filter layer and the light shielding film (black mask) on the sideof the color filter substrate which is opposite to the active matrixsubstrate are bent within the pixel at least once at an angle within arange between 60-120 degrees (except 90 degrees) relative to thealignment direction of the liquid crystal molecule.

According to the first, second, third, fourth and fifth aspects of thepresent invention noted above, the width of the common electrodes thatshield the electric fields of the video signal lines can be decreaseddramatically and the aperture ratio can be improved dramatically.Especially, by utilizing the third, fourth and fifth aspects of thepresent invention, the bumps covering the video signal lines can be usedalong with the spacers. Further, with the use of halftone exposuremethod, the bumps covering the video signal lines and the spacers can beconstructed at the same time, which dramatically shortens the timerequired for the production process. In the conventional technologiesdisclosed by Japanese patent laid-open publication NOs. 2002-258321 and2002-323706 require to construct the photo spacers on the color filtersubstrate which requires an additional production process. The use ofboth the bumps surrounding the video signal lines and the spacers in thepresent invention can simplify the production process especially whenthe liquid crystal cell gap is smaller than 3 micrometers, therebyenabling to dramatically reduce the production cost.

According to the second and fifth aspects of the present invention notedabove, the capacitance between the video signal line and the shieldingcommon electrode can be minimized, thus, it is possible to maximize theaperture ratio while minimizing the distortion of the video signalwaveforms even when the size of the liquid crystal display system isincreased to forty (40) inches or more. Especially, the second and fifthaspects of the present invention are useful to decrease the distortionof the video signal waveforms especially when the liquid crystal cellgap is smaller than 2.5 micrometers.

According to the sixth and eighteenth aspects of the present inventionnoted above, the adhesion strength between the insulation bumps coveringthe video signal lines and the shielding common electrodes is improvedand the problem of film peeling can be prevented, thereby improving theproduction yield. Furthermore, by using the transparent material for theshielding common electrodes, it is possible to allow the light to passthrough the areas around the shielding common electrodes when the liquidcrystal is driven so that the effective transmittance ratio can beimproved, thereby achieving a liquid crystal display device with highbrightness and high contrast.

According to the seventh and nineteenth aspects of the present inventionnoted above, the movement of the hair tips of the rubbing cloth duringthe rubbing alignment treatment can be done smoothly so that it canprevent the occurrence of alignment defects. The conventionaltechnologies disclosed in Japanese patent laid-open Nos. 2002-258321 and2002-323706 do not utilize the taper angle of less than 30 degrees atthe edges of the bumps on the active matrix substrate. As a result, thesmooth movements of the hair tips of the rubbing cloth at edge portionsof bumps of the conventional technology cannot be attained, which causesthe poor alignment. Therefore, it causes the light to leak during theblack display at the portions with the poor alignment and thussignificantly decreases the contrast. According to the presentinvention, the taper angle of the bumps covering the video signal linesis controlled to be less than 30 degrees so that no light leak can occurduring the black display, which makes it possible to attain a highpicture quality with high contrast.

According to the fourth, fifth, eighth, tenth, eleventh, twelfth,sixteenth, seventeenth, twentieth, twenty third and twenty fourthaspects of the present invention noted above, with use of the liquidcrystal drop-feed vacuum attachment alignment device, the liquidcrystals spread smoothly inside the liquid crystal cells during liquidcrystal cell construction, therefore problems associated with residualair bubbles can be decreased. The conventional technology which createsthe liquid crystal cells in the normal atmosphere, and then cuts theminto the individual cell for injecting the liquid crystals in the vacuumatmosphere is not suitable for the liquid crystal cell construction ofthe present invention. The conventional injection technology takes toomuch time, which significantly decreases the production efficiency.Since the liquid crystal drop-feed vacuum attachment alignment device isbeginning to be used in the mass production line today, the structure ofthe present invention can be easily implemented in the actualapplication.

According to the ninth and twenty first aspects of the present inventionnoted above, the problem of film peeling of the shielding commonelectrodes can be avoided when the active matrix substrate and the colorfilter substrate contact each other in the attachment alignment movementduring the liquid crystal drop-feed vacuum attachment process, therebyenabling to minimize the damage to the alignment film.

According to the thirteenth, fourteenth, fifteenth, sixteenth andseventeenth aspects of the present invention noted above, it is possibleto reduce the capacitance created between the shielding commonelectrodes and the scanning lines. Therefore, the aperture ratio can bemaximized while the distortion of the scanning signal waveforms on thescanning lines can be minimized even for the liquid crystal displaydevice of an ultra large size such as forty (40) inches or more.Especially, with use of the fourteenth and seventeenth aspects, it ispossible to maximize the aperture ratio while minimizing the distortionof the signal waveforms both on the video signal lines and the scanninglines.

According to the twenty fifth aspect of the present invention notedabove, the shielding effect can be improved because of the use of theupper layer and lower layer shielding common electrodes that cover thevideo signal lines through the insulation films. Accordingly, thevertical crosstalk can be eliminated even when the width of theshielding common electrodes is decreased and the aperture ratio can beincreased to the maximum level. Because the upper layer shielding commonelectrode has a shielding effect higher than that of the lower layercommon electrode, the highest shielding effect and high aperture ratiocan be achieved by forming the width of the upper layer shielding commonelectrodes larger than that of the lower layer shielding commonelectrodes.

According to the twenty sixth, twenty seventh, twenty eighth, twentyninth and thirtieth aspects of the present invention noted above, it ispossible to rotate the positive dielectric constant anisotropic liquidcrystal molecules in two different directions (right rotation and leftrotation) within a single pixel, thereby enabling to achieve a widerviewing angle. Furthermore, it is possible to significantly decrease thecolor shift phenomenon so that a picture quality suitable for a liquidcrystal display television is achieved. With use of the structure of thepresent invention, the transverse electric field type liquid crystaldisplay device is able to achieve the wider viewing angle, high apertureratio, low cost, high contrast, and high response speed.

According to the thirty first, thirty second, thirty third, thirtyfourth and thirty fifth aspects of the present invention noted above, itis possible to rotate the negative dielectric constant anisotropicliquid crystal molecules in two different directions (right rotation andleft rotation) within a single pixel, thereby enabling to achieve awider viewing angle.

According to the thirty sixth, thirty seventh and thirty eighth aspectsof the present invention noted above, it is possible to prevent thecapacitance created between the shielding common electrodes and thevideo signal line from increasing even when the cell gap of thetransverse electric field type liquid crystal display device becomesless than 3.0 micrometers, thereby decreasing the distortion of thesignal waveforms on the video signal lines. Furthermore, it is possibleto concentrate the electric fields created between the liquid crystaldrive electrodes and the shielding common electrodes to the edge of eachelectrode so that it is possible to drive the liquid crystal moleculeswithout increasing the liquid crystal drive voltage even when the cellgap is less than 3.0 micrometers.

According to the thirty ninth aspect of the present invention notedabove, it is possible to prevent damage to the main seal that wouldtypically arise during the liquid crystal drop-feed vacuum attachmentalignment process. When the spacer bumps are located around theapplication area of the main seal, the spacer bumps function as aprotection wall against the piercing of the liquid crystal. Byincreasing the width of the spacer bumps provided around the applicationarea of the main seal in a closed loop fashion so that it is larger thanthe width of the spacer bumps of the effective pixel area, the effect ofthe protection wall will further increase. Furthermore, because theliquid crystal display device of the present invention does not need tomix the main seal material with glass fibers to determine the cell gaps,it completely eliminates the breakage of wiring due to the pressure ofthe glass fibers mixed in the main seal that would arise when aluminumor aluminum alloy are used as the scanning lines and the video signallines.

According to the fortieth, forty first, forty second, forty third, fortyfourth and forty fifth aspects of the present invention noted above,since it is possible to produce the insulation bump covering the videosignal lines or to produce both the bumps covering the video signallines and the spacer at the same time with use of the halftone exposuretechnique, thus it is possible to reduce the production steps and cost.According to the conventional technologies shown in Japanese patentlaid-open publication Nos. 2002-258321 and 2002-323706, a separateprocess is required for producing the photolithography spacers, whichinevitably increases the production cost.

According to the forty sixth aspect of the present invention notedabove, because the shielding common electrodes are connected in the formof flat surface, it is possible to reduce the impedance. With thisconstruction, it is possible to reduce the thickness of the shieldingcommon electrodes to be as thin as possible. In the case of a dotinversion drive method, the thickness of 300-500 angstroms is sufficientfor the shielding common electrodes. By utilizing this aspect and theseventh and nineteenth aspects of the present invention, the movement ofthe tips of the rubbing cloth hair can be done smoothly during therubbing alignment treatment, which is able to avoid alignment defectsand to completely eliminate the light leakage in the black screen,thereby achieving an image with excellent contrast and a uniformhalftone image display. Furthermore, in the structure in which theshielding common electrodes are connected not only at the right and leftsides of the pixel but also at the top and bottom sides of the pixel asin the present invention, breakage of a portion of the shieldingelectrodes will not cause a line defect on a screen, therefore will notsignificantly affect the image. Therefore, the yield in the productionprocess will be dramatically improved.

According to the forty seventh, seventieth and seventy first aspects ofthe present invention noted above, it is possible to provide atransverse electric field type liquid crystal display device with highpicture quality, high aperture ratio, high response speed, and a widerviewing angle. With the structure of the present invention, it ispossible to rotate the liquid crystal molecules in the two oppositedirections (right rotation and left rotation) without lowering theaperture ratio even when the pitch of the video signal is as small as 50micrometers. The structure of the present invention does not alwaysrequire a black mask corresponding to the video signal line, however, byproviding conductivity to the black mask and to the over coating layer,it is possible to prevent the color filter layer from charging thestatic electricity.

According to the forty eighth aspect of the present invention notedabove, it is possible to simplify the production process by conductingthe processes for leveling the transverse type electric field typeactive matrix substrate and constructing the photolithography spacers atthe same time. The leveling method of the present invention, where thesubstrate is exposed by the ultraviolet ray from the back surface, doesnot leave a leveling layer on the upper layer of the liquid crystaldrive electrodes and the common electrodes. Therefore, the voltage fordriving the liquid crystal does not increase. Because the leveling layeris not left on the upper layer of the liquid crystal drive electrodesand the common electrodes, a polarization effect or a charge trap effectof the organic leveling layer will not occur, which can avoid theproblem of residual image. The movement of the tips of the rubbing clothhair can be done smoothly during the rubbing alignment treatment sincethere are no unevenness on the surface of the active matrix substrate,hence alignment defects will not occur. Thus, an ideal black display canbe achieved since the alignment defects will not occur. Accordingly, itis possible to achieve a display device with high contrast withoutirregularity in displaying the halftone image.

According to the forty ninth, fifty, fifty first, fifty second, fiftythird and fifty fourth aspects of the present invention noted above, itis possible to simplify the production process by performing theleveling of the active matrix substrate and the construction of thephotolithography spacers at the same time during the production of thetransverse electric field type liquid crystal display device. Especiallywith the use of the fifty fourth aspect, significant decrease in thecost can be achieved because the overall process for constructing theactive matrix substrate can be completed with three (3) photomaskingsteps.

By utilizing the back surface exposure leveling (flattening orplanarization) method of the present invention, there remains noleveling layer on the liquid crystal drive electrodes and the commonelectrodes, therefore there is no increase in the liquid crystal drivevoltage. Further, because the leveling layer does not exist on theliquid crystal drive electrodes and the common electrodes, thepolarization effect or the charge trap effect will not occur, therebyeliminating residual images. The movement of the tips of the rubbingcloth hair can be done smoothly during the rubbing alignment treatmentsince there are no uneven areas on the surface of the active matrixsubstrate, hence the alignment defects will not occur.

According to the fifty fifth and fifty sixth aspects of the presentinvention noted above, an optical system for conducting the back surfaceexposure can be constructed easily even when the active matrix substrateis as large as two (2) meters or more. The optical system of the presentinvention is able to easily adjust the degree of light exposure and toexpose uniformly throughout the entire area of the substrate even whenthe size of the substrate is increased. The transverse electric fieldtype liquid crystal display system is highly susceptible to the liquidcell gap, therefore, not only the height of the photolithography spacersbut the degree of flatness around the leveled (planarized) area must becarefully controlled to prevent the unevenness in the halftone imagedisplay. By utilizing the production system of the present invention incombination with a feedback loop, it is possible to produce an activematrix substrate without irregularity in the cell gap.

According to the fifty seventh aspect of the present invention notedabove, by utilizing an ordinary photomask during the halftone exposureprocess, it is possible to form very thin films of the lower layercommon electrodes for shielding the video signal lines and of the commonelectrodes within the pixels as well as to separate the silicon elementsfor the thin film transistors (silicon island) and to create the contactholes at the same time. Further, it is possible to produce the activematrix substrate with high performance without increasing thephotomasking process. Furthermore, by utilizing the ordinary photomaskin the halftone exposure process during the construction of the videosignal lines and the liquid crystal drive electrodes, it is possible toproduce the liquid crystal drive electrodes with a thickness of lessthan 300-500 angstroms, which eliminates the need for the levelingprocess which needs to form the leveling layer, thereby enabling togreatly decrease the production cost.

According to the fifty eighth, fifty ninth, sixtieth, sixty first andsixty second aspects of the present invention noted above, it ispossible to easily reduce the number of steps in the production processof the active matrix substrate without using an expensive lighttransmission adjustable photomask (halftone photomask) but using theordinary photomask. The present invention is applicable not only to atransverse electric field type liquid crystal display device but toother modes of liquid crystal devices, and is also applicable to anactive matrix type organic EL display device, thus its scope ofapplication is very wide. The production method using the halftone shiftexposure apparatus and the halftone shift exposure process of thepresent invention is useful in decreasing the production cost of a largesize display device. The attempt to apply the halftone exposure methodusing a halftone photomask (light transmission adjustable photomask) toa production of a large substrate, traditionally, was not feasible dueto the high cost of the halftone photomask. However, by utilizing themethod of the present invention, it is possible to easily produce thelarge substrate with use of the inexpensive ordinary photomask in thehalftone shift exposure, therefore, the limitation to the application ofhalftone exposure process for a large substrate is eliminated.

According to the sixty third aspect of the present invention notedabove, it is possible to prevent occurrences of air bubbles from beingtrapped within the cells since the height of the spacer bumps willchange with the changes of the volume of the liquid crystal even whenthe volume of the liquid crystal within the liquid crystal celldecreases because of low temperature. Especially, by increasing therange of plastic deformation, the volume inside the liquid crystal cellcan easily change in response to the amount of drop of the liquidcrystal during the pressurizing process under the atmospheric pressurein the liquid crystal injection vacuum attachment alignment process,thereby completely eliminating the residual air bubble problem.

According to the sixty fourth, sixty fifth, sixty sixth, sixty seventh,sixty eighth and sixty ninth aspects of the present invention notedabove, it is possible to keep the thickness of all of the electrodes fordriving the liquid crystal molecules of the transverse electric fieldtype liquid crystal display device to about 300-500 angstroms. As aresult, the production cost can be reduced since the leveling process isno longer necessary. All of the electrodes for driving the liquidcrystal molecules can be produced at the same time at the last stage ofthe production process and thus, the same material can be used for allof the drive electrodes, therefore, the chemical potential energy of theelectrodes are identical throughout. This enables the liquid crystalmolecules be driven by an alternating current (AC) voltage, which isable to prevent the occurrence of the residual image problem. All of theelectrodes needed for driving the liquid crystal molecules can be formedby very thin films (less than 500 angstroms), therefore, the movement atthe tips of the rubbing cloth hair during the rubbing alignmenttreatment can be performed smoothly and the alignment defects can beavoided. Therefore, the light leakage during the black level display canbe completely eliminated, thereby achieving the display with highcontrast.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B are cross sectional views showing the halftone exposurephotomask and the positive photoresist after development on the activematrix substrate according to the present invention.

FIGS. 2A-2B are cross sectional views showing the halftone exposurephotomask and the positive photoresist after development on the activematrix substrate according to the present invention.

FIG. 3 is a flow chart showing the four operational steps involved inthe photomasking process in the conventional technology.

FIG. 4 is a flow chart showing the four operational steps involved inthe photomasking processes in the present invention.

FIGS. 5A-5C are cross sectional views showing an example of the separatetwo-step exposure method and the structure of the positive photoresistafter development in the present invention.

FIGS. 6A-6C are cross sectional views showing another example of theseparate two-step exposure method and the structure of the positivephotoresist after development in the present invention.

FIGS. 7A-7E are cross sectional views showing an example of productionprocess for forming the video signal lines and the common electrodes inthe present invention.

FIGS. 8A-8E are cross sectional views showing another example ofproduction process for forming the video signal lines and the commonelectrodes in the present invention.

FIG. 9 is a perspective view showing the structure of a laser opticalsystem used in the laser alignment marking process of the presentinvention.

FIG. 10 is a schematic diagram showing the laser optical systememploying a fθ lens used in the laser alignment marking process of thepresent invention.

FIG. 11 is a schematic diagram showing the positions of the laseralignment markers in the present invention formed by the laser opticalsystem.

FIG. 12 is a schematic diagram showing the structure of the opticalsystem used for the laser beam scanning exposure in the presentinvention.

FIG. 13 is a schematic diagram showing the structure of the titleroptical system (inverted real image) for the ultraviolet ray exposuremethod using a micro mirror array according to the present invention.

FIG. 14 is a schematic diagram showing the structure of the multi-lensoptical system (noninverted real image) for the ultraviolet ray exposuremethod using a micro mirror array according to the present invention.

FIG. 15 is a plan view showing an example of structure of the multi-lensscanning exposure system used in the present invention.

FIG. 16 is a timing chart for explaining the operation of the micromirror array for the ultraviolet light transmission adjustment bycontrolling the time widths in accordance with the present invention.

FIG. 17 is a plan view showing an example of structure of the scanningexposure device used in the multi-lens scanning exposure system in thepresent invention.

FIG. 18 is a plan view showing an example of structure in scanningexposure device used in the direct halftone exposure method of thepresent invention in which a photomask is not used.

FIG. 19 is a cross sectional view showing the scanning exposure deviceused in the separate two-step exposure method of the present invention.

FIGS. 20A-20B are schematic diagrams showing the principle of theexposure in the direct halftone exposure of the present invention and across sectional structure of the photoresist after the development.

FIG. 21 is a circuit diagram showing an example of configuration in thestatic electricity protection circuit formed by thin film transistors.

FIG. 22 is a circuit diagram showing another example configuration inthe static electricity protection circuit formed by thin filmtransistors.

FIG. 23 is a plan view showing an example of the structure of the staticelectricity protection circuit formed by the thin film transistorsaccording to the present invention.

FIG. 24 is a plan view showing another example of the structure of thestatic electricity protection circuit formed by the thin filmtransistors according to the present invention.

FIG. 25 is a plan view showing a further example of the structure of thestatic electricity protection circuit formed by the thin filmtransistors according to the present invention.

FIG. 26 is a plan view showing a further example of the structure of thestatic electricity protection circuit formed by the thin filmtransistors according to the present invention.

FIGS. 27A-27F are cross sectional views showing an example of the activematrix substrate production flow involved in the four-step photomaskingprocess of the present invention.

FIGS. 28A-28F are cross sectional views showing an example of the activematrix substrate production flow involved in the three-step photomaskingprocess of the present invention.

FIG. 29 is a plan view showing an example of structure in the scanningexposure device used in the mixed exposure method of the presentinvention.

FIG. 30 is a plan view showing another example of structure in thescanning exposure device used in the mixed exposure method of thepresent invention.

FIG. 31 is a plan view showing an example of structure of the transverseelectric field type active matrix array substrate produced using themixed exposure method of the present invention.

FIGS. 32A-32E are schematic diagrams showing the principle of thehalftone shift exposure method of the present invention and a crosssectional structure of the photoresist after the development.

FIGS. 33A-33B are schematic diagrams showing an example of principle ofthe halftone shift exposure method of the present invention.

FIGS. 34A-34B are schematic diagrams showing another example ofprinciple of the halftone shift exposure method of the presentinvention.

FIGS. 35A-35E are schematic diagrams showing the principle of thehalftone shift exposure method of the present invention and a crosssectional structure of the photoresist after the development.

FIGS. 36A-36F are cross sectional views showing an example of theproduction flow involved in the four-step photomasking process in theconventional technology.

FIGS. 37A-37B are schematic diagrams showing a further example ofprinciple of the halftone shift exposure method of the presentinvention.

FIGS. 38A-38B are schematic diagrams showing an example of principle ofthe separate two-step exposure method of the present invention.

FIGS. 39A-39B are schematic diagrams showing another example ofprinciple of the separate two-step exposure method of the presentinvention.

FIGS. 40A-40B are schematic diagrams showing a further example ofprinciple of the separate two-step exposure method of the presentinvention.

FIGS. 41A-41B are schematic diagrams showing a further example ofprinciple of the separate two-step exposure method of the presentinvention.

FIG. 42 is a flow chart showing an example of the production flowinvolved in the four-step photomasking process of the present invention.

FIGS. 43A-43B are schematic diagrams showing a further example ofprinciple of the separate two-step exposure method of the presentinvention.

FIGS. 44A-44B are schematic diagrams showing a further example ofprinciple of the separate two-step exposure method of the presentinvention.

FIG. 45 is a cross sectional view showing an example of structure in thetransverse electric field type liquid crystal panel including thespacers covering the video signal lines and the shielding electrodesformed on the spacers according to the present invention.

FIG. 46 is a cross sectional view showing another example of structurein the transverse electric field type liquid crystal panel including thespacers covering the video signal lines, and the shielding electrodesformed on the spacers according to the present invention.

FIG. 47 is a cross sectional view showing an example of structure in thetransverse electric field type liquid crystal panel in the presentinvention.

FIG. 48 is a cross sectional view showing another example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 49 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 50 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 51 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 52 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 53 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 54 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 55 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 56 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 57 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 58 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 59 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 60 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 61 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 62 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 63 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 64 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 65 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 66 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 67 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 68 is a cross sectional view showing a further example of structurein the transverse electric field type liquid crystal panel in thepresent invention.

FIG. 69 is a plan view showing an example of structure in the transverseelectric field type liquid crystal display device according to thepresent invention.

FIG. 70 is a plan view showing another example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 71 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 72 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 73 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 74 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 75 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 76 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 77 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 78 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 79 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 80 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 81 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 82 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 83 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 84 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 85 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 86 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 87 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 88 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 89 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 90 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 91 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 92 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 93 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 94 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 95 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 96 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device-accordingto the present invention.

FIG. 97 is a plan view showing a further example of structure in thetransverse electric field type liquid crystal display device accordingto the present invention.

FIG. 98 is a graph showing the characteristics concerning the thicknessof the negative photoresist after development used in the halftoneprocess of the present invention.

FIG. 99 is a graph showing the characteristics concerning the line widthof the negative photoresist after development used in the halftoneprocess of the present invention.

FIGS. 100A-100B are cross sectional views showing an example of crosssectional structures of the photomask used in the halftone exposure ofthe present invention and the negative photoresist after thedevelopment.

FIGS. 101A-101B are cross sectional views showing another example ofcross sectional structures of the photomask used in the halftoneexposure of the present invention and the negative photoresist after thedevelopment.

FIGS. 102A-102C are cross sectional views showing an example of separatetwo-step exposure method of the present invention and the crosssectional structure of the negative photoresist after the development.

FIGS. 103A-103C are cross sectional views showing another example ofseparate two-step exposure method of the present invention and the crosssectional structure of the negative photoresist after the development.

FIG. 104 shows an enlarged cross sectional view of the bump covering thevideo signal line and the photolithography spacer constructed on thebump in the present invention.

FIG. 105 is a flow chart showing the production flow involved in thefour-step photomasking process of the present invention.

FIGS. 106A-106F are cross sectional views showing the active matrixsubstrate production flow involved in the four-step photomasking processusing the halftone shift exposure method of the present invention.

FIGS. 107A-107D are cross sectional views showing the process involvedin the transverse electric field type liquid crystal panel which isplanarized with use of the back surface exposure method of the presentinvention.

FIG. 108 is a cross sectional view showing an example of structure inthe transverse electric field type liquid crystal panel of the presentinvention.

FIG. 109 is a cross sectional view showing another example of structurein the transverse electric field type liquid crystal panel of thepresent invention.

FIG. 110 is a cross sectional view showing a further example ofstructure in the transverse electric field type liquid crystal panel ofthe present invention.

FIG. 111 is a cross sectional view showing a further example ofstructure in the transverse electric field type liquid crystal panel ofthe present invention.

FIG. 112 is a cross sectional view showing a further example ofstructure in the transverse electric field type liquid crystal panel ofthe present invention.

FIG. 113 is a cross sectional view showing a further example ofstructure in the transverse electric field type liquid crystal panel ofthe present invention.

FIGS. 114A-114C are cross sectional views showing the process forplanarizing the active matrix substrate and forming the photolithographyspacers at the same time with use of the halftone back surface exposuremethod of the present invention.

FIG. 115 is a plan view showing an example of structure in thetransverse electric field type liquid crystal display device of thepresent invention.

FIG. 116 is a flow chart showing an example of production flow involvedin the six-step photomasking process of the present invention.

FIG. 117 is a flow chart showing another example of production flowinvolved in the six-step photomasking process of the present invention.

FIG. 118 is a flow chart showing a further example of production flowinvolved in the six-step photomasking process of the present invention.

FIG. 119 includes a cross sectional view and a plan view showing thestructure of the transverse electric field type liquid crystal panel ofthe present invention in the vicinity of the main seal.

FIG. 120 is a schematic diagram showing the relationship between thealignment direction and the rotation direction of the liquid crystalmolecules of the positive anisotropic dielectric material used in thetransverse electric field type liquid crystal panel of the presentinvention.

FIG. 121 is a schematic diagram showing the relationship between thealignment direction and the rotation direction of the liquid crystalmolecules of the negative anisotropic dielectric material used in thetransverse electric field type liquid crystal panel of the presentinvention.

FIG. 122 is a plan view showing an example of structure of the colorfilter used in the transverse electric field type liquid crystal displaypanel of the present invention.

FIG. 123 is a plan view showing another example of structure of thecolor filter used in the transverse electric field type liquid crystaldisplay panel of the present invention.

FIG. 124 is a flow chart showing an example of production flow involvedin the three-step photomasking process of the present invention.

FIG. 125 is a flow chart showing an example of production flow involvedin the five-step photomasking process of the present invention.

FIG. 126 is a flow chart showing an example of production flow involvedin the four-step photomasking process of the present invention.

FIG. 127 is a flow chart showing an example of production flow involvedin the three-step photomasking process of the present invention.

FIG. 128 is a flow chart showing an example of production flow involvedin the five-step photomasking process of the present invention.

FIG. 129 is a flow chart showing an example of production flow involvedin the six-step photomasking process of the present invention.

FIGS. 130A-130C are cross sectional views showing the process forplanarizing the active matrix substrate and forming the photolithographyspacers at the same time with use of the halftone back surface exposuremethod of the present invention.

FIG. 131 is a cross sectional view showing an example of structure ofthe halftone back surface exposure device according to the presentinvention.

FIG. 132 is a plan view showing an example of structure of the halftoneback surface exposure device according to the present invention.

FIG. 133 is a cross sectional view showing another example of structureof the halftone back surface exposure device according to the presentinvention.

FIG. 134 is a plan view showing another example of structure of thehalftone back surface exposure device according to the presentinvention.

FIG. 135 is a schematic diagram showing an overall system configurationof the halftone back surface exposure device of the present invention.

FIG. 136 is a flow chart showing an overall process of the halftone backsurface exposure method of the present invention.

FIG. 137 is a cross sectional view showing an example of opticalstructure in the white light interferometer used in the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in more detail with respectto the preferred embodiments with reference to the accompanyingdrawings.

First Embodiment

FIGS. 45, 46, 47, 70, 72, 74, 76, 78 and 80 show the first embodiment ofthe present invention. FIGS. 45-47 are cross sectional views showingexamples of structure in the transverse electric field type liquidcrystal panel including spacers covering the video signal lines and theshielding electrodes formed on the spacers according to the presentinvention. FIGS. 70, 72, 74, 76, 78 and 80 are plan views showingexamples of structure in the transverse electric field type liquidcrystal display device according to the present invention.

In FIGS. 45-47, a numeral 9 denotes a gate insulation film, a numeral 51denotes a video signal line, a numeral 53 denotes a liquid crystal driveelectrode (pixel electrode), a numeral 55 denotes a passivation film, anumeral 66 denotes a glass substrate in the side of color filter, anumeral 67 denotes a black mask (light shielding film), a numeral 68denotes a color filter layer, a numeral 69 denotes a leveling layer inthe side of color filter, a numeral 70 denotes an alignment film in theside of color filter, a numeral 71 denotes an alignment film in the sideof TFT (thin film transistor) array substrate, a numeral 72 denotes acommon electrode (upper layer) for shielding the electric field producedby the video signal line, a numeral 73 denotes a spacer bump forcovering the video signal line, a numeral 74 denotes a common electrodewithin the pixel (upper layer), a numeral 75 denotes a common electrode(lower layer) for shielding the electric field produced by the videosignal line, and a numeral 76 denotes a glass substrate in the side ofthe TFT array.

Further in FIGS. 70, 72, 74, 76, 78 and 80, a numeral 15 denotes ascanning line, a numeral 49 denotes a common electrode within the pixel(lower layer), a numeral 79 denotes a shielding electrode formed on bothside walls of the spacer bump, a numeral 80 denotes a TFT (thin filmtransistor) element, a numeral 81 denotes a contact hole for connectingthe shielding common electrode and the lower layer common electrode, anda numeral 82 denotes the lower layer electrode.

The lower layer common electrodes 75 for shielding the electric field ofthe video signal line is constructed at the same time as the scanninglines 51 on the same layer. The video signal line 51 and the liquidcrystal drive electrodes 53 are constructed at the same time on the samelayer. The upper layer shielding common electrodes 72 for shielding theelectric field of the video signal line and the common electrodes 74within the pixel are constructed at the same time on the same layer. Inthe example of FIG. 46, as opposed to the example of FIG. 45, the upperlayer shielding common electrodes 72 have a wider electrode width thanthat of the lower layer shield common electrodes 75. The structure shownin FIG. 46 is able to provide a larger aperture ratio than that of thestructure shown in FIG. 45.

The video signal line 51 and the liquid crystal drive electrodes 53 arecovered by the passivation layer 55, and the spacer bumps 73 areconstructed in a manner to cover (surround) the video signal lines 51.The upper layer shielding common electrodes 72 can cover the spacerbumps 73 completely as shown in FIGS. 70 and 72, or the upper layer wallshielding common electrodes 79 can be placed at both side walls of thespacer bumps 73 as shown in FIGS. 76 and 80. When the height of thespacer bumps 73 is less than 3.0 micrometers or when the size of theliquid crystal panel is larger than 30 inches, the construction of theactive matrix substrate using the upper layer wall shielding commonelectrodes 79 shown in FIGS. 76 and 80 would be preferable to moreeffectively prevent distortions in the video signal waveform.

The spacer bumps 73 shown in the cross sectional views of FIGS. 45, 46and 47 actually have a gentle taper angle θ as shown in the crosssectional view of FIG. 104. A distance L1 from an edge of the spacerbump 73 to an edge of the video signal line 51 is preferably at least 3micrometers. The taper angle θ of the spacer bump 73 in FIG. 104 ispreferably 30 degrees or smaller so that the movement of the tips ofrubbing cloth hairs can be performed smoothly during the rubbingalignment treatment, thereby avoiding occurrence of alignment defectiveareas. It is preferable to make the distance L2 between an edge of thespacer bump 77 and the upper layer shielding common electrodes 79 belarger than 0.5 micrometers. Basically, the larger the distance L2, thebetter shielding effects will be available. When the lower shieldingcommon electrodes do not exist such as in the example of FIG. 47, thedistance L2 of about 10 micrometers is sufficient.

It is imperative for the present invention that the cross sectionalshape of the spacer bump 73 has an upward projection such as an oval,half oval, hyperbolic, or parabolic shape. This upward projection allowsthe spacer bump 73 to easily deform when a pressure caused by anatmospheric pressure is applied during a liquid crystal drop vacuumattachment alignment process. Materials utilized for forming the spacerbump 73 should be a type that allows the height of the spacer bump 73 touniformly deform in the range between 0.1 micrometers and 0.5micrometers when the atmospheric pressure is applied thereto, otherwise,a problem of residual air bubble will arise.

As shown in FIGS. 70, 74, and 76, it is especially important that thespacer bump 73 does not reside around the area of the crossing pointbetween the scanning line 15 and the video signal line 51 because theliquid crystal has to be diffused in this area where the spacer bump 73does not exist. In the example of FIGS. 78 and 80, an area where thespacer bump 73 does not exist is created at around the center of thepixel. Although the dripped liquid crystal will be diffused in thisarea, this structure of FIGS. 78 and 80 may not be suitable for a largescreen liquid crystal panel, since the capacitance between the upperlayer shielding common electrode 72 and the video signal line 51 willincrease.

The construction as shown in FIG. 74 in which the spacer bumps are alsoconstructed over the scanning lines 15 and the upper layer commonelectrodes 72 are connected together between the upper and lower pixelsand right and left pixels is suitable for a large screen liquid crystaldisplay device. Since the shielding common electrodes 72 are connectedin a mesh like manner, in the liquid crystal display device using thismethod, even when there is a breakage in the line, the resultant linefault will be negligible in the practical use.

It is preferable that the dielectric constant of the spacer bumps 73 isas small as possible, however, 3.3 or less should be sufficient for anactual implementation. In the case where the monomer or oligomer used asa material for forming the spacer bump 73 includes at least onebenzo-cyclobutene structure or its dielectric material, or at least onefluorene skeleton or its dielectric material, then it is possible tocomposite the dielectric material with the dielectric constant of lessthan 3.3.

FIGS. 86 and 87 are plan views showing further examples of structure inthe transverse electric field type liquid crystal display device of thefirst embodiment of the present invention. In the example of FIGS. 86and 87, the size of the spacer bump 73 is minimized. In the drawings, anumeral 83 denotes a common electrode (upper layer) for shielding theelectrical field produced by the video signal lines 51. As noted above,the numeral 75 denotes a lower layer shield common electrode. Becausethe size of the spacer bump 73 is minimized, the dielectric material oflarge dielectric constant can be used.

Second Preferred Embodiment

FIGS. 48, 49, 50, 71 and 75 show the transverse electric field typeliquid crystal panel of the second embodiment of the present invention.FIGS. 48-50 are cross sectional views thereof and FIGS. 71 and 75 areplan views thereof. In the second embodiment, the common electrodewithin the pixel is formed under the passivation layer and the gateinsulation film. The lower layer common electrodes 75 for shielding theelectric field of the video signal lines 51 and the common electrodes 49within the pixel for driving the liquid crystal element are constructedat the same time on the same layer where the scanning lines are formed.The video signal lines 51 and the liquid crystal drive electrodes 53 areconstructed at the same time on the same layer.

In the example of FIG. 49, as opposed to the example of FIG. 48, theupper layer shielding common electrodes 72 have a wider width than thatof the lower layer shielding common electrodes 75. Therefore, thestructure shown in FIG. 49 is able to achieve a larger aperture ratiothan the structure shown in FIG. 48. As shown in FIGS. 48-50, in thesecond embodiment, since the common electrode 49 within the pixel isconstructed on the layer lower than the passivation layer 55 and thegate insulation layer 9, a voltage required to drive the liquid crystaltends to become higher.

With the structure used in the second embodiment of the presentinvention, as shown in FIGS. 71 and 75, the liquid crystal driveelectrode 53 is sandwiched by the lower layer common electrode 82connected to the common electrode 49 within the pixel and the uppershielding layer common electrode 72 through the gate insulation layerand the passivation layer. With this structure, it is possible to have alarge hold capacity in a small area, thereby enabling to achieve a largeaperture ratio.

Third Preferred Embodiment

FIGS. 51, 52, 53, 69, 73, 77, 79 and 81 show the transverse electricfield type liquid crystal panel in the third embodiment of the presentinvention, FIGS. 51-53 are cross sectional views thereof and FIGS. 69,73, 77, 79 and 81 are plan views thereof. In the drawings, a numeral 77denotes an insulation (dielectric) bump covering the video signal line51, a numeral 78 denotes a spacer formed on the bump 77 covering thevideo signal line 51, and a numeral 79 denotes a shielding commonelectrode formed on the side walls of the bump 77. The structure in thethird embodiment is basically the same as that of the first embodimentnoted above except that the spacer bump 73 in the first embodiment isseparated to two structures, one is the insulation bump 77 that coversthe video signal line 51 and the other is the spacer 78 that determinesthe liquid crystal cell gap.

One of the features of the present invention is that the insulation bump77 that covers the video signal line 51 and the spacer 78 thatdetermines the liquid crystal cell gap can be produced through the samephotolithography process. By utilizing a light transmission adjustablephotomask (halftone photomask) as shown in FIGS. 1A-1B and 2A-2B andpositive photoresist, it is possible to produce the cross sectionalshape of the bump 77 and spacer 78 such as the one shown in FIG. 104. Itis also possible to produce the cross sectional shape the bump 77 andspacer 78 shown in FIG. 104 by incorporating a two-step exposuretechnique (half exposure and supplemental exposure) as shown in FIGS.5A-5C and FIGS. 6A-6C with use of an ordinary photomask and the positivephotoresist.

In FIGS. 1A-1B, FIGS. 2A-2B, a numeral 1 denotes a silica glasssubstrate forming the photomask, a numeral 2 denotes a metal layer (Cror Mo) on the glass substrate for controlling the amount of light passtherethrough, a numeral 3 denotes a translucent (halftone or gray) areaof the photomask formed by slit patterns, a numeral 4 denotes atranslucent (halftone or gray) area of the photomask (a-Si, TiSix, MoSixor Ti), a numeral 5 denotes a transparent area of the photomask, anumeral 6 denotes an area on a positive photoresist layer afterdevelopment where UV exposure is blocked, a numeral 7 denotes an area onthe positive photoresist layer after development where the UV exposureis made through the halftone (translucent) area of the photomask, and anumeral 8 denotes an area where the positive photoresist is completelyremoved after development, a numeral 9 denotes a gate insulation film, anumeral 10 denotes a thin film semiconductor layer (non-doped layer), anumeral 11 denotes a thin film semiconductor layer (doped layer, i.e.,ohmic contact layer), a numeral 12 denotes a barrier metal layer, and anumeral 13 denotes a low resistance metal layer.

As shown in FIGS. 1A and 1B, unlike the opaque metal area 2 whichcompletely blocks the UV light transmission, the area 3 allows the UVlight to pass by a small amount (halftone) depending on the density ofthe slits. Thus, it is possible to create the area 6 where thephotoresist is intact after development as well as the area 7 where thephotoresist is removed but still remained (halftone exposed area). Asshown in FIGS. 2A and 2B, the photomask includes the opaque area 2 andthe translucent layer 4, and the transparent area 5. Thus, thephotoresist is completely removed at the area 8 corresponding to thetransparent area 5, the photoresist is removed halfway at the area(halftone exposed area) 7 corresponding to the translucent area 4, andthe photoresist is unaffected in the area 6 corresponding to the opaquearea 2. With use of the light transmission adjustable photomask shown inFIGS. 1A-1B and 2A-2B, the spacer bump 73 having the cross sectionalstructure shown in FIG. 104 can be created by one photolithographyprocess.

As noted above, the spacer bump 73 having the cross sectional structureshown in FIG. 104 can also be created with use of the normal photomaskthrough the two-step exposure method shown in FIGS. 5A-5C and 6A-6C. Thephotomask in this example has no halftone area and is configured only bythe glass substrate 1 and the opaque metal layer 2. In FIGS. 5A-5C and6A-6C, a numeral 19 denotes a UV light, a numeral 20 denotes an area onthe positive photoresist layer after development where the UV lightexposure is completely blocked, a numeral 21 denotes an area where thephotoresist is removed after being completely exposed by the UV light19, a numeral 22 denotes an area on the positive photoresist layer afterdevelopment where the UV light exposure is made incompletely (underexposure), and a numeral 23 denotes an area where the photoresist ispartially exposed by the second step of UV exposure, a numeral 24denotes an area where the photoresist is completely removed by the firstand second steps of UV light exposure, and a numeral 25 denotes an fθlens used in the second exposure step of FIG. 6B.

In the example of FIGS. 5A-5C, in the first exposure step of FIG. 5A,the photoresist area 20 is not exposed because of the photomask metal(opaque) 2 and the photoresist area 21 is exposed by the UV light 19 inthe degree that the photoresist 21 will not be completely removed afterexposure (under exposure). In the second exposure step shown in FIG. 5B,the photoresist area 21 that has been exposed in the first step isfurther exposed at the portion 23 at the position corresponding to thetransparent portion of the photomask. Thus, as shown in FIG. 5C, thephotoresist is completely removed at the area 24, thereby creating thespacer 78 and bump 77 having the cross sectional structure shown in FIG.104.

In the example of FIGS. 6A-6C, the first exposure step (under exposure)is the same as that of FIG. 5A. In the second exposure step shown inFIG. 6B, the photoresist area 21 that has been exposed in the first stepis further exposed at the portion 23 with use of the fθ lens. It shouldbe noted that the photomask is not used in the second exposure step ofFIG. 6B. The fθ lens has a function of producing focus points on thesame flat surface of a relatively large area on the substrate. Thus, therelatively large area of the photoresist can be exposed uniformlywithout using a photomask. Accordingly, as shown in FIG. 6C, thephotoresist is completely removed at the area 24, thereby creating thespacer 78 and bump 77 having the cross sectional structure shown in FIG.104.

However, it is difficult, although not impossible, to produce the bumpand spacer with sufficient flexibility when using the positivephotoresist. Therefore, one of the features of the present invention isto provide a method to utilize negative photoresist that has a moreflexible characteristic to produce the cross sectional shape shown inFIG. 104 with a singe photolithography process. It should be noted thattypes of negative photoresist that are susceptible to oxygen fault cansuffer, when a quantity of exposure light is small, from acceleratedphotopolymerization by a small amount of ultraviolet light at the areascontacting with the glass substrate while it can suffer from lack ofreaction in the photopolymerization by the oxygen in the atmosphere atthe areas exposed to the atmosphere.

FIGS. 98 and 99 show the characteristics for this type of negativephotoresist in terms of film thickness and line width with respect toparameters of the amount of exposure light and the length of thedevelopment. Using this type of negative photoresist and a lighttransmission adjustment photomask (halftone photomask) as shown in FIGS.100A-100B and 101A-101B, it is possible to achieve the shape of thespacer and bump shown in FIG. 104. The example of FIGS. 100A-100Bcorresponds to the process shown in FIGS. 2A-2B where the photomaskincludes the transparent portion 5, translucent portion (halftone) 4,and the opaque portion 2. The example of FIGS. 101A-101B corresponds tothe process shown in FIGS. 1A-1B where the photomask includes the slitpattern (halftone photomask) 3 for incompletely exposing the photoresistin addition to the transparent portion and the opaque portion.

Alternatively, it is also possible to utilize a two-step exposuretechnique using the partial area complete exposure step and the halfexposure step as shown in FIGS. 102A-102C and 103A-103C. The example ofFIGS. 102A-102C corresponds to the process shown in FIGS. 5A-5C wherethe two different photomasks are used in the first and second exposuresteps. The example of FIGS. 103A-103B corresponds to the process shownin FIGS. 6A-6C where the fθ lens 25 is used in the second exposure step.In FIGS. 102A-102C and 103A-103C, a numeral 85 denotes an area of thenegative photoresist after development where the photoresist is intactby the complete exposure of UV light, a numeral 86 denotes an area onthe negative photoresist where the photoresist is removed but stillremains by the incomplete exposure of UV light, and a numeral 87 denotesan area on the negative photoresist which is not exposed because of theopaque pattern 2 on the photomask. In this manner, since the expensivelight transmission adjustment photomask (halftone photomask) does notneed to be used, but an inexpensive ordinary photomask can be used inthis example to produce the spacer 78 and bump 77 having the shape ofFIG. 104.

FIGS. 116-118 show examples of production flow using the six-stepphotomasking process for implementing the third embodiment of thepresent invention. In the example of FIG. 116 which incorporates thehalftone exposure technique, at step S51, gate electrodes (scanning linepatterns) and common electrodes are formed at the same time. At stepS52, the silicon elements are separated from a semiconductor thin filmlayer for forming the thin film transistors. Then, in step S53, throughthe first and second halftone exposure processes, source and drainelectrodes of the thin film transistors and liquid crystal driveelectrodes are formed at the same time.

In the next step S54, the bumps that cover the video signal lines forshielding the electric field and the photolithography spacers thatdefine the liquid crystal cell gap are formed through the first andsecond halftone exposure processes. At step S55, contact holes forterminal portions and circuits for static electricity protection areformed through an etching process. In the last step S56, the commonelectrodes for shielding the video signal lines, the transparent commonelectrodes within the pixel, and the gate and data electrodes at thesame time.

In the example of FIG. 117 which incorporates the halftone exposuretechnique, at step S61, gate electrodes (scanning line patterns) andcommon electrodes are formed at the same time through the first andsecond halftone exposure processes. At step S62, the silicon elementsare separated from the semiconductor thin film layer for forming thethin film transistors. Then, in step S63, through the first and secondhalftone exposure processes, source electrodes and drain electrodes ofthe thin film transistors, and liquid crystal drive electrodes areformed at the same time.

In the next step S64, the bumps that cover the video signal lines forshielding the electrical field and the photolithography spacers areformed through the first and second halftone exposure processes. At stepS65, contact holes for terminal portions and circuits for staticelectricity protection are formed through an etching process. In thelast step S66, the common electrodes for shielding the video signallines, gate electrodes and data electrodes are formed at the same time.

In the example of FIG. 118, at step S71, gate electrodes (scanning linepatterns) and common electrodes are formed at the same-time. At stepS72, the silicon elements are separated from the semiconductor thin filmlayer for forming the thin film transistors. Then, in step S73, sourceelectrodes and drain electrodes are formed at the same time. In the nextstep S74, the bumps that cover the video signal lines and thephotolithography spacers are formed. At step S75, contact holes forterminal portions and circuits for static electricity protection areformed. In the last step S76, the common electrodes for shielding thevideo signal lines, common electrodes within the pixels, gate electrodesand data electrodes are formed at the same time.

Still referring to FIG. 104, preferably, the thickness h1 of the bump 77that covers the video signal line 51 is preferably in the range between1.5 micrometers and 3.5 micrometers, and the spacer 78 projecting fromthe bump 77 has a height h2 of about 0.2-2.0 micrometers. As to thedensity of the spacers 78, about one (1) to seventy five (75) of themwill be formed in an area of one square millimeter. The size of the areafor the spacer is within a range between 200 square micrometers and2,000 square micrometers within one square millimeter. It is importantthe upper layer shielding common electrodes will not be positioned atthe area where the spacer is projected. The height h2 of the spacers 78constructed on the bump 77 must be able to deform in the range of0.2-0.5 micrometers when a pressure is applied from the atmosphereduring a liquid crystal injection vacuum attachment alignment process.If the spacer 78 is covered by the upper layer shielding commonelectrode 79, a problem may arise where the deformation of the spacer 78by the atmospheric pressure causes the upper layer shielding commonelectrodes to peel off.

Examples of material used for forming the upper layer shielding commonelectrodes 79 include conductive material with visible lighttransmission of 20 percent or more such as titanium metal compoundincluding titanium nitride (TiNx), titanium oxide nitride (TiOxNy),titanium silicide (TiSix), titanium silicide nitride (TiSixNy), or metaloxide transparent conductive material mainly composed of indium oxide(In2O3) or zinc oxide (ZnO).

As shown in FIG. 104, similar to the first embodiment described above,it is important to have the taper angle θ at an edge portion of the bump77 to be as small as possible ordinarily this taper angle θ should beset to less than 30 degrees. By keeping the taper angle small, movementsof the tips of the rubbing cloth hair can be performed smoothly duringthe rubbing alignment treatment process, which eliminates alignmentdefects. When the taper angle θ is larger than 45 degrees, instancesoccur where the tips of rubbing cloth hairs cannot make contact with thesurface around the tapered area and may result in areas of alignmentdefects. If such alignment defects occur, such an area causes light toleak during the black display, which seriously lowers the contrast ofthe display. Structures disclosed by Japanese patent laid-openpublication numbers 2002-258321 and 2002-323706 do not allow for smoothmovements of the tips of the rubbing cloth hairs, therefore, instancesoccur where the tips of the rubbing cloth hairs cannot reach around thetapered area and cannot completely prevent the occurrence of alignmentdefects.

As shown in FIG. 77 the shape of the spacer does not have to be circularbut can be an oval shape. In the example of FIGS. 79 and 81, the shapeof the spacer is circular. When the spacer 78 is provided over the bump77 that covers the video signal line as in the present invention, it ispossible to construct the bump 77 at the intersecting points of thescanning lines 15 and the video signal line 51 since there is nothing toobstruct the diffusion of the liquid crystal during the liquid crystalinjection vacuum attachment and alignment process. It is also possibleto construct the bumps 77 on top of the scanning lines as shown in FIGS.79 and 81 so that the bumps are arranged in a mesh like fashionthroughout the substrate. When the upper layer shielding commonelectrode 72 completely covers or overlaps the video signal line 51 andscanning line 15 through the bump 77, the light shielding film on thecolor filter substrate side becomes unnecessary, which can increase theaperture ratio to the maximum level.

As shown in the example of FIG. 81, the structure in which the upperlayer shielding common electrodes 79 are constructed on both side wallsof the bump 77 that covers the scanning line 15 and on both side wallsof the bump 77 that covers the video signal line 51 is best suited foran ultra large screen liquid crystal display device. This is becausethis structure can minimize the distortion in the video signal linewaveforms and the scanning line waveforms.

Preferred Embodiment 4

FIGS. 54, 55 and 56 are the cross sectional views showing the structuresof the transverse electric field type liquid crystal panel in the fourthembodiment of the present invention. This structure is basically thesame as that of the second embodiment described above except that thespacer bump 73 of the second embodiment is separated into an insulationbump 77 that covers the video signal line and a spacer 78 thatdetermines the liquid crystal cell gap.

In the second embodiment noted above, the dielectric (insulation) bump73 that covers the video signal line 51 also functions as a spacer todetermine the cell gaps. In the fourth embodiment, however, as in thethird embodiment, the functions of the dielectric (insulation) bump 77that covers the video signal line and the spacer 78 that determines theliquid cell gap are completely separated. The dielectric bump 77 of thethird embodiment and fourth embodiment can completely cover the scanningline 15 and the video signal line 51. Therefore, by constructing anupper layer shielding common electrode 79 on both side walls of theinsulation bump 77, it is possible to keep the distortion of signalwaveform by the video signal line 51 and the scanning lines to theminimum level, and thus, achieve the maximum aperture ratio.

The spacer 78 shown in FIGS. 54, 55, and 56 are not covered by the upperlayer shielding common electrodes 79 so that the dielectric material isprojected by itself. This structure is advantageous in that the commonelectrode layer does not peel off when the pressure from the atmosphereis applied during liquid crystal injection vacuum attachment alignmentprocess.

As has been described in the foregoing, in the structures of the firstthrough fourth embodiments, the video signal line 51 and the liquidcrystal drive electrode 53 are completely covered by the gate insulationlayer 9 and the passivation layer 55 in the up and down directions.Further, the video signal line and the liquid crystal drive electrodeare provided on the layer different from that of the shielding commonelectrodes and the common electrodes within the pixel. Therefore, evenwhen a pattern fault occurs, the possibility of shorting each otherbecomes unlikely, thereby minimizing the possibility of pixel defect.

Preferred Embodiment 5

FIGS. 57, 58 and 59 are cross sectional views showing the structures ofthe transverse electric field type liquid crystal panel in the fifthembodiment of the present invention. In this embodiment, the videosignal line 51 and the liquid crystal drive electrode 53 are not coveredby the passivation layer 55 unlike the first to fourth embodiments. Onlythe video signal line 51 is covered by the dielectric spacer bump 73.According to the present invention, the video signal line 51 and theliquid crystal drive electrode 53 can be constructed at the same time.Alternatively, the drain electrode of the thin film transistor can beconstructed with the video signal line 51 at the same time and then theliquid crystal drive electrode 53 can be constructed simultaneously withthe upper layer shielding electrode 72 and the common electrode 74within the pixel at the same time after the construction of the spacerbump 73. Either construction method is applicable to the fifthembodiment. With the structure of the present invention, there is noneed for opening a contact hole to connect the drain electrode of thethin film transistor with the liquid crystal drive electrode.

Preferred Embodiment 6

FIGS. 60, 61 and 62 are cross sectional views showing the structures ofthe transverse electric field type liquid crystal panel in the sixthembodiment of the present invention. As with the fifth embodiment, thevideo signal line 51 and the liquid crystal drive electrode 53 are notcovered by the passivation layer 55 unlike the first to fourthembodiments. Only the video signal line 51 is covered by the dielectricspacer bump 73. The sixth embodiment is different from the fifthembodiment only in that the common electrode 49 within the pixel isconstructed simultaneously with the scanning line and the lower layershielding common electrode 75 on the same layer.

Preferred Embodiment 7

FIGS. 63, 64 and 65 are cross sectional views showing the structures ofthe transverse electric field type liquid crystal panel in the seventhembodiment of the present invention. This structure is basically thesame as that of the fifth embodiment except that the spacer bump 73 isseparated into the dielectric (insulation) bump 77 that covers the videosignal line and the spacer 78 that determines the liquid crystal cellgap.

Preferred Embodiment 8

FIGS. 66, 67 and 68 are cross sectional views showing the structures ofthe transverse electric field type liquid crystal panel in the eighthembodiment of the present invention. This structure is basically thesame as that of the sixth embodiment except that the spacer bump 73 isseparated into the dielectric (insulation) bump 77 that covers the videosignal line and the spacer 78 that determines the liquid crystal cellgap.

Preferred Embodiment 9

FIGS. 108, 109, 110 show the sectional view and plan view of thetransverse electric field type liquid crystal panel of the eighthembodiment of the present invention. In the example of FIGS. 108, 109and 110, a numeral 90 denotes a liquid crystal drive electrode. As notedabove with reference to FIGS. 45-47, a numeral 9 denotes a gateinsulation film, a numeral 51 denotes a video signal line, a numeral 53denotes a liquid crystal drive electrode, a numeral 55 denotes apassivation film, a numeral 66 denotes a glass substrate in the side ofcolor filter, a numeral 67 denotes a black mask (light shielding film),a numeral 68 denotes a color filter layer, a numeral 69 denotes aleveling layer in the side of color filter, a numeral 70 denotes analignment film in the side of color filter, a numeral 71 denotes analignment film in the side of TFT array substrate, a numeral 72 denotesan upper layer common electrode, a numeral 73 denotes a spacer bumpcovering the video signal line, a numeral 74 denotes a common electrodewithin the pixel, a numeral 75 denotes a lower layer common electrode,and a numeral 76 denotes a glass substrate in the side of TFT array.

In the embodiment of FIGS. 108-110, the video signal line 51 and theliquid crystal drive electrodes 90 are constructed on a different layerrelative to the passivation layer 55. The upper layer shielding commonelectrodes 72 and the common electrode 74 within the pixel and theliquid crystal drive electrode 90 are constructed on the same layer atthe same time. The liquid crystal drive electrode 90 is connected to thedrain electrode of the thin film transistor through the contact hole.

The ninth embodiment of the present invention is most effective inleveling (flattening) the irregularity in the areas around the displaypixels. By forming the upper layer shielding common electrodes 72, thecommon electrode 74 within the pixel, and the liquid crystal driveelectrode 90 at the same time with use of the transparent electrodematerial (ITO or IZO) with a thickness of 300-500 angstroms, it ispossible to dramatically increase the effective aperture ratio. In thetransverse electric field mode, when the width of the electrode is smallsuch as about 3-5 micrometers, it is possible for a majority of theliquid crystal molecules above the electrode to rotate because of afringe field effect so that the light can transmit from the areas aroundthe electrode. Because of this fringe field effect, the structure shownin FIG. 109 is most effective in improving the aperture ratio, therebyachieving the display with high contrast.

With the structures shown in FIGS. 109 and 110, the fringe field effectis also effective around the edge areas of the upper layer shieldingcommon electrode 72, which promotes the light transmission around theedge areas of the upper layer shielding common electrode 72, therebyimproving the aperture ratio. The black mask 67 provided on the side ofthe color filter substrate is not essential to the structure of thisembodiment. It is preferable that the width of the black mask 67 is thesame as that of the dielectric spacer bump 73 or slightly smaller. It isimportant to keep the taper angle θ of the spacer bump 73 to be lessthan 30 degrees to prevent occurrences of alignment defects in therubbing alignment treatment.

It is preferable that the spacer bump is not formed at the intersectionarea of the scanning line and the video signal line so that the liquidcrystal can smoothly diffuse during the liquid crystal injection vacuumattachment alignment process. A problem of residual air bubble can occurif the spacer bump 73 is not fabricated by material that allows thespacer bump to deform 0.1-0.5 micrometers when a pressure from theatmosphere is applied thereto.

Preferred Embodiment 10

FIGS. 111, 112 and 113 are cross sectional views and FIG. 115 is a planview, respectively, showing the structures of the transverse electricfield type liquid crystal panel in the tenth embodiment of the presentinvention. This structure is basically the same as that of the ninthembodiment except that the spacer bump 73 of the ninth embodiment isseparated into an insulation (dielectric) bump 77 that covers the videosignal line and a spacer 78 that determines the liquid crystal cell gap.

As shown in FIG. 115, the upper layer shielding common electrodes 72,the common electrode 74 within the pixel, and the liquid crystal driveelectrode 90 are produced on the same layer at the same time. The liquidcrystal drive electrode 90 is connected to the drain electrode of thethin film transistor though a contact hole 93. The upper layer shieldingcommon electrode is not provided above the spacer 78. The upper layershielding common electrodes 72 are connected to each other on thescanning lines in up/down and right/left directions in a mesh likefashion. In FIG. 115, the upper layer shielding common electrode 72covers the video signal line 51 almost completely. It is also possibleto form the upper layer shielding common electrode on the side walls ofthe dielectric bump 77 such as the one shown in FIG. 81. In anapplication of a large screen liquid crystal display panel of 30 inchesor larger, the construction in which the upper layer shielding commonelectrodes are placed at the side walls are preferred because thisstructure is able to decrease the distortion in the video signal linewaveforms.

Preferred Embodiment 11

FIGS. 69-81 and FIG. 115 are plan views showing the structure of thetransverse electric field type liquid crystal display panel in theeleventh embodiment of the present invention. In this structure, thevideo signal line 51, the upper layer shielding common electrode 72, thecommon electrode 74 within the pixel and the liquid crystal driveelectrode 90 are bent within a pixel at least once at an angle within0-30 degrees except 0 degree with respect to the alignment direction ofthe liquid crystal molecules. In the eleventh embodiment, positivedielectric constant anisotropic liquid crystals are used in which thealignment direction of the liquid crystal molecules is almostperpendicular to the direction of the scanning lines.

FIG. 120 is a schematic diagram showing the relationship between thealignment direction and the rotation direction of the liquid crystalmolecules of positive anisotropic dielectric material used in thetransverse electric field type liquid crystal panel of the presentinvention. In FIG. 120, a numeral 97 denotes an alignment direction ofthe liquid crystal molecule, a numeral 98 denotes a positive dielectricconstant anisotropic liquid crystal molecule, and a numeral 105 denotesan angle between the pixel electrode (liquid crystal drive electrode 53)and the alignment direction of the crystal molecule 98. As shown in FIG.120, the liquid crystal molecules are able to rotate in the right andleft directions, which contributes to increase the viewing angle whiledecreases the color shift at the same time.

FIG. 121 is a schematic diagram showing the relationship between thealignment direction and the rotation direction of the liquid crystalmolecules of negative anisotropic dielectric material used in thetransverse electric field type liquid crystal panel of the presentinvention. In FIG. 121, a numeral 97 denotes an alignment direction ofthe liquid crystal molecule, a numeral 99 denotes a negative dielectricconstant anisotropic liquid crystal molecule, and a numeral 106 denotesan angle between the pixel electrode (liquid crystal drive electrode 53)and the alignment direction of the crystal molecule 99.

As shown in FIG. 121, by using the negative dielectric constantanisotropic liquid crystal with the alignment direction of the liquidcrystal molecules in parallel with the direction of the scanning lines,the liquid crystal molecules are able to rotate in the right and leftdirections, which contributes to increase the viewing angle whiledecreases the color shift at the same time. In the arrangement of FIG.121, the video signal line, the liquid crystal drive electrode, thecommon electrodes within the pixel, and the upper layer common electrodeare bent at least once at an angle between 60 degrees and 120 degreesexcept 90 degrees, with respect to the alignment direction of the liquidcrystal molecule in a given pixel.

Preferred Embodiment 12

FIGS. 82, 84, 92., 93, 94 and 95 are plan views showing the structure ofthe transverse electric field type liquid crystal panel in the twelfthembodiment of the present invention. In this structure, the video signalline is straight while the upper layer shielding common electrode,common electrode within the pixel, and the liquid crystal driveelectrode are bent within a pixel at least once at an angle within arange between 0-30 degrees except 0 degree with respect to the alignmentdirection of the liquid crystal molecules. In the twelfth embodiment,positive dielectric constant anisotropic liquid crystals are used inwhich the alignment direction of the liquid crystal molecules issubstantially perpendicular to the direction of the scanning line. Asshown in FIG. 120, the liquid crystal molecules are able to rotate inthe right and left directions, which contributes to increase the viewingangle while decreases the color shift at the same time.

In the twelfth embodiment, as shown in FIG. 121, by using the negativedielectric constant anisotropic liquid crystals with the alignmentdirection of the liquid crystal molecules in parallel with the directionof the scanning lines, the liquid crystal molecules are able to rotatein the right and left directions, which contributes to increase theviewing angle while decreases the color shift at the same time. In thearrangement of this embodiment, the liquid crystal drive electrode, thecommon electrodes within the pixel, and the upper layer common electrodeare bent at least once at an angle between 60 degrees and 120 degreesexcept 90 degrees, with respect to the alignment direction of the liquidcrystal molecule in a given pixel.

Preferred Embodiment 13

FIGS. 83, 85, 88, 89, 90, 91, 96 and 97 are plan views showing thestructure of the transverse electric field type liquid crystal panel inthe thirteenth embodiment of the present invention. In this structure,as to one pixel, the video signal line and the upper layer shieldingcommon electrode are straight while the common electrode within thepixel and the liquid crystal drive electrode are bent at least once atan angle within a range between 0-30 degrees except 0 degree withrespect to the alignment direction of the liquid crystal molecules. Inthe thirteenth embodiment, positive dielectric constant anisotropicliquid crystals are used in which the alignment direction of the liquidcrystal molecules is substantially perpendicular to the direction of thescanning line. As shown in FIG. 120, the liquid crystal molecules areable to rotate in the right and left directions, which contributes toincrease the viewing angle while decreases the color shift at the sametime.

In the thirteenth embodiment, as shown in FIG. 121, by using thenegative dielectric constant anisotropic liquid crystal with thealignment direction of the liquid crystal molecules in parallel with thedirection of the scanning lines, the liquid crystal molecules are ableto rotate in the right and left directions, which contributes toincrease the viewing angle while decreases the color shift at the sametime. In the arrangement of this embodiment, the liquid crystal driveelectrode and the common electrode within the pixel are bent at leastonce at an angle between 60 degrees and 120 degrees except 90 degrees,with respect to the alignment direction of the liquid crystal moleculein a given pixel.

Preferred Embodiment 14

It is also possible that the video signal line, the upper layershielding common electrode, and the common electrode within the pixelare straight while only the liquid crystal drive electrode is bent atleast once at an angle within a range 0-30 degrees except 0 degree withrespect to the alignment direction of the liquid crystal molecules. Inthis arrangement, positive dielectric constant anisotropic liquidcrystals are used in which the alignment direction of the liquid crystalmolecules is substantially perpendicular to the direction of thescanning line. As shown in FIG. 120, the liquid crystal molecules areable to rotate in the right and left directions, which contributes toincrease the viewing angle while decreases the color shift at the sametime.

In the fourteenth embodiment, as shown in FIG. 121, by using thenegative dielectric constant anisotropic liquid crystal with thealignment direction of the liquid crystal molecules in parallel with thedirection of the scanning lines, the liquid crystal molecules are ableto rotate in the right and left directions, which contributes toincrease the viewing angle while decreases the color shift at the sametime. In this arrangement, only the liquid crystal drive electrode isbent at least once at an angle between 60 degrees and 120 degrees except90 degrees, with respect to the alignment direction of the liquidcrystal molecule in a given pixel.

Preferred Embodiment 15

With respect to the structure described in the above regarding theeleventh embodiment, it is also possible that the common electrodewithin the pixel is obviated and only one line of liquid crystal driveelectrode exists within a pixel, and further, the video signal line, theupper layer shielding common electrode, and the liquid crystal driveelectrode are bent at least once at an angle within a range 0-30 degreesexcept 0 degree with respect to the alignment direction of the liquidcrystal molecules. As shown in FIG. 120, the liquid crystal moleculesare able to rotate in the right and left directions, which contributesto increase the viewing angle while decreases the color shift at thesame time. In this arrangement, positive dielectric constant anisotropicliquid crystals are used in which the alignment direction of the liquidcrystal molecules is substantially perpendicular to the direction of thescanning line. The fifteenth embodiment is suited for the production ofsuper high resolution display device with a pixel pitch of 50micrometers or smaller.

In the fifteenth embodiment, as shown in FIG. 121, by using the negativedielectric constant anisotropic liquid crystal with the alignmentdirection of the liquid crystal molecules in parallel with the directionof the scanning lines, the liquid crystal molecules are able to rotatein the right and left directions, which contributes to increase theviewing angle while decreases the color shift at the same time. In thisarrangement, the video signal line, the upper layer shielding commonelectrode, and the single line of the liquid crystal drive electrode arebent at least once at an angle between 60 degrees and 120 degrees except90 degrees, with respect to the alignment direction of the liquidcrystal molecule in a given pixel.

In the structure of the color filter substrate used in the eleventh andfifteenth embodiments, as shown in FIGS. 122 and 123, the lightshielding film (black mask) 101 and the color filter layer 68 are bentin a similar manner to the video signal line. More particularly, theblack mask 100 that covers the scanning line is straight and the blackmask 101 covers the video signal line is bent as noted above. Accordingto the present invention, the spacer bump and the bump covering thevideo signal line are also bent similarly to the vide signal line. Inthe case where the upper layer shielding common electrode covers thevideo signal line completely, the light leakage will not occur even whenthe black mask corresponding to the video signal line is not used, thusit is possible to eliminate the black mask. When the upper layershielding common electrodes covers both the video signal line and thescanning lines completely, the light leakage will not occur even whenthe black mask is not used, thus, it is sufficient that only the colorfilter is bent similarly to the video signal line.

Preferred Embodiment 16

FIG. 119 shows a cross sectional view and a plan view of the transverseelectric field type liquid crystal panel in the sixteenth embodiment ofthe present invention. In FIG. 119, a numeral 66 denotes a glasssubstrate in the side of color filter, a numeral 67 denotes a black mask(light shield film), a numeral 68 denotes a color filter layer, anumeral 69 denotes a leveling layer in the side of the color filter, anumeral 70 denotes an alignment film in the side of the color filter, anumeral 71 denotes an alignment film in the side of TFT array substrate,a numeral 76 denotes a glass substrate in the side of TFT array, anumeral 78 denotes a spacer formed on the bump covering the video signalline, a numeral 94 denotes a photolithography spacer having a ringshape, a numeral 95 denotes a photolithography spacer having a circularshape, a numeral 96 denotes a main seal for forming the liquid crystalcell.

The spacer bump 94 having a closed loop shape is formed at the positionthat overlaps the boarder of the black mask (light shielding film) thatsurrounds the outer most display area. The width of 100-500 micrometerswill be sufficient for the spacer bump 94, although the width of thespacer bump should not be too small. FIG. 119 only shows one closedlooped spacer bump 94, however, two or more of them can also beincorporated. In the area of the main seal 96, many spacer bumps 95having a circular shape are provided. By utilizing the structure of thepresent invention, glass fibers that determine the cell gap does notneed to be introduced. Because the glass fibers are not mixed therein,this structure can prevent the occurrence of line breakage even when thevideo signal line and the scan lines are fabricated by soft materialsuch as aluminum alloy. Further, by utilizing the structure of thepresent invention, the main seal does not invade the areas of the blackmask, thus, the main seal can be completely hardened by ultravioletrays. In this structure, since the spread of impurities from the mainseal can be effectively suppressed, it is able to improve thereliability.

Preferred Embodiment 17

FIGS. 32, 33, 34, 35 and 106 show the transverse electric field typeliquid crystal panel in the seventeenth embodiment of the presentinvention. FIGS. 32A-32E and 35A-35E are plan views and cross sectionalviews showing the principle of the halftone shift exposure method of thepresent invention and the structure of the photoresist after thedevelopment. FIGS. 33A-33B and 34A-34B are plan views showing otherexamples of the halftone shift exposure method of the present invention.FIGS. 106A-106F are cross sectional views showing the production flowinvolved in the four-step photomasking process using the halftone shiftexposure method of the present invention.

In FIGS. 32A-32E and 35A-35E, a numeral 1 denotes a silica glasssubstrate forming a photomask, a numeral 2 denotes a metal layer (opaquemask pattern) on the glass substrate 1, a numeral 19 denotes a UV light,a numeral 20 denotes an area on the positive photoresist layer afterdevelopment where the UV light exposure is completely blocked, a numeral21 denotes an area where the photoresist is completely removed, anumeral 22 denotes an area on the positive photoresist layer afterdevelopment where the UV light exposure is made through the underexposure (incomplete exposure) step, and a numeral 62 denotes an area onthe photoresist which has been exposed in the first under exposure step,and a numeral 63 denotes an area on the photoresist which has beencompletely exposed through both the first and second under exposuresteps.

In the present invention, as shown in FIG. 32A, the mask pattern 2 isdesigned to have a gap l between a source electrode and a drainelectrode where a gap distance l is equal to a half of the channellength of the thin film transistor. That is, if the channel length ofthe thin film transistor is desired to be 6 micrometers, the gapdistance 1 of 3 micrometers is used to create the source electrode andthe drain electrode. By using an ordinary photomask, a first exposurestep is conducted for the positive resist by an under exposure(incomplete exposure) process as shown in FIG. 32B. Then, in FIG. 32C,either the photomask or the glass substrate is shifted horizontally (Xdirection) by a distance equal to or slightly larger than the gapdistance l between the source electrode and the drain electrode. Then, asecond exposure step is conducted as shown in FIG. 32D by the samedegree of under exposure as that of the first exposure step.

Because the positive photoresist is not completely exposed by the UVlight in the first exposure since it is the under exposure process, thephotoresist layer underneath the area 62 shown in FIG. 32B remains afterthe development. Further, because the under exposure step is repeatedtwo times as noted above, the area 63 of the photoresist shown in FIG.32D which has experienced the under exposure by two times is completelyexposed and removed after the development. Thus, when the development isdone, the positive photoresist with the cross sectional shape shown inFIG. 32E can be achieved.

FIGS. 33A-33B and FIGS. 34A-34B show similar concepts. In the example ofFIGS. 33A-33B, either the photomask or the glass substrate is shiftedhorizontally (Y direction) by a distance equal to the gap distance lbetween the source electrode and the drain electrode. In the example ofFIGS. 34A-34B, either the photomask or the glass substrate is shifted intwo horizontal directions (both X and Y directions) by a distance Δx andΔy, each being equal to the gap distance l or slightly larger than thegap distance l between the source electrode and the drain electrode.

In the example of FIGS. 35A-35E, a thin pattern is provided in the gapbetween the source electrode and the drain electrode of the photomask.The pattern width L of the thin pattern and a gap distance l between thethin pattern and either the source electrode or drain electrode have arelationship of L<l. It is preferable that the gap distance l isslightly larger than the pattern width L for the under exposure process.Similar to the example of FIGS. 32A-32E, after the first under exposureprocess, either the photomask or the glass substrate is shifted by adistance equal to or slightly larger than the gap distance l, the secondunder exposure process is conducted.

When the development is done, the positive photoresist with the crosssectional shape shown in FIG. 35E can be achieved. Preferably, theamount of shift distance and the amount of exposure are adjusted so thatthe channel area of the thin film transistor becomes as flat aspossible. Further, it is preferable that the shift distance and theexposure amount are adjusted so that, in FIGS. 32E and 35E, thethickness of the area 20 of the positive photoresist that has not beenexposed is 1.5-2.5 micrometers and the thickness of the half exposedarea (under exposed area) 22 on the positive photoresist is 0.2-0.5micrometers.

FIGS. 106A-106F are cross sectional views showing the process forproducing the thin film transistor elements using the halftone shiftexposure method of the present invention. In FIGS. 106A-106F, a numeral6 denotes an area on a positive photoresist layer after developmentwhere UV exposure is blocked, a numeral 7 denotes an area on thepositive photoresist layer after development where the UV exposure ismade through the halftone shift exposure (under exposure), a numeral 9denotes a gate insulation film, a numeral 10 denotes a thin filmsemiconductor layer (non-doped layer), a numeral 11 denotes a thin filmsemiconductor layer (doped layer, i.e., ohmic contact layer), a numeral15 denotes a scanning line, a numeral 50 denotes a scanning lineterminal, a numeral 51 denotes a video signal line, a numeral 54 denotesa scanning line terminal drive circuit contact electrode, a numeral 64denotes a drain electrode, and a numeral 65 denotes a transparent pixelelectrode.

In this example, the production process utilizes four photomaskingsteps. The processes for producing a thin film resistor using the lighttransmission adjustment photomask with the halftone exposure is shown inFIGS. 36A-36F. The process of FIGS. 106A-106F involves a process ofshifting the exposure position by moving either the photomask or glasssubstrate. Although the overall process is similar to that of FIGS.36A-36F, the process of FIGS. 106A-106F achieves the halftone exposurewithout using the light transmission adjustment photomask (halftonephotomask).

Prior to the start of the process of FIGS. 106A-106F, the scanning lines15 and the scanning terminals 50 are formed on a TFT array glasssubstrate (not shown), which can be done by a process shown in FIGS.7A-7E or FIGS. 8A-8E as will be explained later. In FIG. 106A, the gateinsulation film 9, the thin film semiconductor layer (non-doped layer)10 and the thin film semiconductor layer (ohmic contact layer) 11 arerespectively deposited by, for example, a CVD plasma device. Thepositive photoresist 6 is coated and the halftone shift exposure (underexposure) using the ordinary photomask is conducted in the mannerdescribed with reference to FIGS. 32A-32E, 33A-33B, 34A-34B and 35A-35Eso that the thicker positive photoresist 6 and the thinner positivephotoresist 7 are created.

In FIGS. 106B and 106C, through a dry etching process and plasma ashingprocess, the silicon elements for the thin film transistors areseparated from the semiconductor layer. In FIG. 106D, the drainelectrode 64 of the thin film transistor and the video signal line 51are formed by further conducting the etching process. In FIG. 106E,through the dry etching, contact holes are created over the scanningline terminals 50. In FIG. 106F, the scanning line drive circuitelectrodes 54 and the transparent pixel electrodes 65 are formed.

In this embodiment, the passivation coverage is improved because theedge portions of the thin film semiconductor layer are formed in a steplike shape. The conventional light transmission adjustment photomask isexpensive and is not practical for an ultra large screen liquid crystaltelevision. However, as noted above, the halftone shift exposure methodof the present invention can be conducted with use of inexpensiveordinary photomasks.

The seventeenth embodiment of the present invention noted above can beapplied not only to the liquid crystal display device. For example, thepresent invention is also applicable to the production processes oforganic EL (electro-luminescence) display devices or active matrixsubstrates for X ray detectors, which can dramatically decrease theproduction cost.

FIGS. 17 and 19 show an example of a scan exposure device that can beused in the halftone shift exposure process of the seventeenthembodiment. FIG. 17 is a plan view showing the structure of the scanningexposure device used in the multi-lens scanning exposure system forimplementing the seventeenth embodiment of the present invention, andFIG. 19 is a cross sectional view showing the scanning exposure deviceof FIG. 17. In FIGS. 17 and 19, a numeral 19 denotes a UV light, anumeral 44 denotes a multi-lens exposure module, a numeral 45 denotes anordinary photomask, a numeral 46 denotes an X-Y stage, and a numeral 48denotes an optical fiber cable.

When the glass substrate is large, if the photomask of the same size asthat of glass substrate is used, the overall cost becomes too high.Thus, in such a case, the photomask 45 which is smaller than the glassplate is used which is shifted in X and Y directions by driving the X-Ystage 46. Since the scanning exposure device of FIGS. 17 and 19 has aplurality of exposure lens arranged in a row, by scanning the exposurelens, it is possible to expose the glass substrate of any size.

The ordinary photomask 45 is a photomask which has no function ofadjusting the light transmission unlike the photomask (halftonephotomask) 1 of FIGS. 1A and 2A. In the halftone shift exposure methodof the present invention, the photomask 45 can be shifted or thesubstrate on the X-Y stage 46 can be shifted. The halftone shiftexposure method can also be implemented by using a mirror projectionscan exposure device. The multi-lens scan exposure device shown in FIGS.17 and 19 is suitable for the halftone shift exposure method of thepresent invention because the resolution of the positive photoresist canbe improved. With the conventional technology using the lighttransmission adjustment photomask, the halftone exposure method usingthe mirror projection scan exposure device with lower resolution is moresuited.

Preferred Embodiment 18

FIGS. 13-16, 18 and 20 show examples of scanning exposure device withoutusing a photomask in accordance with the eighteenth embodiment of thepresent invention. FIG. 13 shows a structure of the titler opticalsystem (inverted real image) for the ultraviolet ray exposure methodusing a micro mirror array, FIG. 14 shows a structure of the multi-lensoptical system (noninverted real image) for the ultraviolet ray exposuremethod using a micro mirror array, FIG. 15 is a plan view showing thestructure of the multi-lens scanning exposure system, FIG. 16 is atiming chart for explaining the operation of the micro mirror array forthe ultraviolet light transmission adjustment by time width control,FIG. 18 is a plan view showing the scanning exposure device used in thedirect halftone exposure method without using a photomask, and FIGS. 20Aand 20B show the principle of the direct halftone exposure of thepresent invention using the exposure device of FIG. 18.

In FIGS. 13-16, 18 and 20, a numeral 19 denotes a UV light, a numeral 20denotes an area on the positive photoresist layer after developmentwhere the UV light exposure is completely blocked, a numeral 21 denotesan area where the photoresist is completely exposed, a numeral 22denotes an area on the positive photoresist layer after developmentwhere the UV light exposure is made through the halftone exposureprocess, a numeral 37 denotes a projection lens, a numeral 38 denotes aglass substrate for TFT array, a numeral 39 denotes a positivephotoresist layer., a numeral 40 denotes a micro mirror array device(DMD module), a numeral 41 denotes a micro mirror, a numeral 42 denotesa time length during which the micro mirror 41 is in operation, anumeral 43 denotes a time length for rewriting the data during which themicro mirror 41 is not in operation, a numeral 44 denotes a multi-lensprojection exposure module (non-inverted real image), a numeral 46denotes an X-Y stage, and a numeral 47 denotes a UV light source.

In the eighteenth embodiment, the scanning exposure device includes aplurality of reflective mirror devices 40 which are arranged in achecker board manner where each mirror device has micro-mirrors formedin a two dimensional manner. As noted above, the scanning exposuredevice of the present invention does not require the photomask forproducing the pattern on the glass substrate. The UV light 19 from thelight source 47 is reflected by the micro-mirrors 41 on the micro-mirrorarray device 40 in the exposure system of FIG. 14. In the exposuresystem of FIG. 15, the UV light 19 passes through the multi-lensprojection exposure module 44 which produces a non-inverted real imageand projects the image on the positive photoresist 39 on the glasssubstrate 38. Thus, the photoresist 39 is exposed by the UV light 19 forthe image produced by the projection exposure module 44. In the exposuresystems of FIGS. 14, 15 and 18, the degree of UV light applied to thephotoresist 39 is regulated by the time lengths as shown by the timingchart of FIG. 16.

As shown in the time chart of FIG. 16, the movement of the micro mirrors41 can be controlled one by one. By using this reflective mirror deviceto alter the exposure timing of the UV ray to the positive photoresist,a multi-level halftone exposure method such as shown in FIGS. 20A-20Bcan be performed. As described above, in the eighteenth embodiment, itis possible to easily conduct the multi-level halftone exposure methodfor a large area without using the expensive light transmissionadjustment (halftone) photomask.

The major difference between the optical system of FIG. 13 and theoptical system of FIG. 14 resides in that the optical system of FIG. 13involves the inverted real image while the optical system of FIG. 14involves the non-inverted real image. The optical system of FIG. 13 maybe sufficient for use as a titler for locally exposing a simple imagesuch as text data. However, for a scanning exposure system to expose thecomplicated patterns on the substrate, the optical system ofnon-inverted real image such as the one shown in FIG. 14 must be usedfor producing fine and accurate patterns on the substrate.

Preferred Embodiment 19

FIGS. 37A-37B and FIGS. 43A-43B show nineteenth embodiment of thepresent invention. FIGS. 37A-37B are plan views showing an example ofprinciple of the halftone shift exposure method of the presentinvention. FIGS. 43A-43B are plan view showing a further example ofprinciple of the two-step exposure method of the present invention. Moreparticularly, FIGS. 37A-37B and FIGS. 43A-43B show the structure of anordinary photomask for producing the scanning line, the lower layershielding common electrode and the common electrode within the pixel bythe halftone shift exposure method in the seventeenth embodimentdescribed above. FIGS. 37A-37B and FIGS. 43A-43B also show thedistribution of the amount of light exposed during the half shiftexposure process.

In this exposure process, a first under exposure step is conducted withuse of an ordinary photomask. After the first under exposure, thephotomask is shifted in parallel with the scanning line by the distanceequal to the width of the common electrode. Then, the second underexposure step is conducted preferably with the same amount of light asthat of the first exposure step. After the development, there remains anarea having a thick positive photoresist, an area having a thin positivephotoresist, and an area having no positive photoresist.

FIGS. 7A-7E and FIGS. 8A-8E are cross section views showing theprocesses to create electrodes of two different thicknesses using thehalftone shift exposure method. Metals or alloys that can be selectivelyetched are constructed in two or three layers and two differentthickness of positive photoresist are constructed using the halftoneshift exposure of the present invention to construct a non-exposed area20 and an incompletely exposed area 22 (FIGS. 32E and 35E). With use ofthe etching and ashing process for the positive photoresist andselective etching technology, the electrodes having two differentthickness are produced.

The process shown in FIGS. 7A-7E and 8A-8E will be repeated for formingelectrodes on different layers on the TFT array glass substrate. Forexample, the process of FIGS. 7A-7E or 8A-8E precedes the process ofFIGS. 106A-106F described above so that the process of FIGS. 106A-106Fstarts after creating the scanning line 15 and scanning line terminal50. In FIGS. 7A-7E and FIGS. 8A-8E, a numeral 26 denotes lower electrodematerial, a numeral 27 denotes low resistance electrode material, anumeral 28 denotes an upper electrode material. As noted above, anumeral 20 denotes an area of the photoresist which is not exposed bythe UV light, and a numeral 22 denotes an area of the photoresist whichis incompletely exposed (halftone exposure).

In the process of FIGS. 7A-7E and FIGS. 8A-8E, the lower electrodematerial (barrier metal) 26 is incorporated because it is not possibleto directly connect the doped semiconductor n+a-Si layer to purealuminum or aluminum alloy. An example of material for the barrier metalis titanium (Ti). An alloy of titanium and molybdenum or an alloy ofmolybdenum and tungsten is also possible for the barrier metal. In thecase of using an aluminum alloy for the electrode material 27, thestructure of FIG. 7A will be sufficient since there arise no problem indirect connection with ITO (indium tin oxide).

However, when the low resistance electrode material 27 is configured bypure aluminum, there arises a problem of contact defect because aluminumoxide is formed at the contact surface. To overcome this problem, theupper electrode material 28 is formed as shown in FIG. 8A. An example ofmaterial for the upper electrode 28 is molybdenum. Therefore, the basicdifference between the examples of FIGS. 7A-7E and FIGS. 8A-8E is thatthe example of FIGS. 8A-8E includes the upper electrode material 28additionally, although the remaining production process is the same.

In the example of FIGS. 7A-7E, two metal layers are formed on thesubstrate, one is the lower electrode layer 26 and the other is the lowresistance electrode layer 27. For example, the lower electrode layer 26is made of titanium (Ti) and the low resistance electrode layer 27 ismade of aluminum neodymium nickel (Al—Nd—Ni) or aluminum carbon nickel(Al—C—Ni). In FIG. 7A, through the halftone shift exposure method, forexample, the positive photoresist of two different thickness areas 20and 22 are created.

Then, as shown in FIG. 7B, the low resistance electrode layer 27 isetched through a wet etching process and the lower electrode layer 26 isetched through a dry etching process. Then, in FIG. 7C, the thinnerphotoresist area 22 is removed through, for example, a dioxide plasmaashing process while leaving the thicker photoresist area 20. The wetetching process is performed again for the low resistance electrodelayer 27 as shown in FIG. 7D. Lastly, the positive photoresist iscompletely removed through the ashing process as shown in FIG. 7E.

In the example of FIGS. 8A-8E, three metal layers are formed on thesubstrate, the first one is the lower electrode layer 26, the second oneis the low resistance electrode layer 27, and the third one is the upperelectrode layer 28. For example, the lower electrode layer 26 is made oftitanium (Ti), the low resistance electrode layer 27 is made of purealuminum (Al), and the upper electrode layer 28 is made of molybdenum(Mo). In FIG. 8A, through for example, the halftone shift exposuremethod, the positive photoresist of two different thickness areas 20 and22 are created. The process of FIGS. 8B-8E are the same as that of FIGS.7B-7E, thus the explanation thereof is omitted here.

In performing the halftone shift exposure method of the presentinvention, the first exposure and the second exposure use the samephotomask for producing the scanning line, shielding common electrode,and common electrode within the pixel. Thus, in determining thepositions of the first exposure and the second exposure, it is onlynecessary to shift the photomask by a small horizontal movement in onedirection. In other words, there is no need to construct an alignmentmark on the glass substrate for positioning two different photomaskssince only one photomask has to be used. Therefore, it is possible toreduce the time and cost in the production process.

Preferred Embodiment 20

FIGS. 38A-38B, 39A-39B, 40A-40B, 41A-41B and 44A-44B show example ofdistribution of light exposure when the halftone shift exposure methodin the twentieth embodiment of the present invention is conducted withuse of two or more ordinary photomasks, i.e, without using the lighttransmission adjustable photomask (halftone photomask) such as shown inFIGS. 1A and 2A. This example shows the case where the halftone shiftexposure method of the present invention is applied to the productionprocess of the scanning lines and the shielding common electrodes. Inimplementing this method, one or more alignment marks need to beprovided inside the glass substrate since the first exposure and thesecond exposure use photomasks different from one another.

FIG. 9 shows a device that directly writes alignment marks in the glasssubstrate. FIG. 10 shows the principle underlining the device of FIG. 9for writing the alignment marks inside the glass substrate. In FIG. 11,the alignment marks are formed on the areas outside the metal depositionfor construction of the scanning lines and the shielding commonelectrodes. In FIGS. 9, 10 and 11, a numeral 25 denotes an fθ lens, anumeral 29 denotes a laser light source, a numeral 30 denotes a beamformatter, a numeral 31 denotes a galvanomirror, a numeral 32 denotes alaser beam, a numeral 33 denotes a mark pattern formed within the glasssubstrate, and a numeral 38 denotes the glass substrate for TFT array.The laser marking utilized in the present invention is disclosed in moredetail in Japanese patent laid-open publication No. 11-267861. It isimportant to form the alignment marks inside the glass substrate ratherthan the surface of the glass substrate for improving the productionefficiency.

In this embodiment, with use of the different photomasks for the firstand second under exposure steps, the positive photoresist pattern of twodifferent thickness will be created after the development. Through theprocesses shown in FIGS. 7A-7E and FIGS. 8A-8E as noted above, the metalelectrodes with two levels of thickness will be produced by etching,ashing and selective etching of the positive photoresist.

Preferred Embodiment 21

FIGS. 27A-27F and FIGS. 28A-28F show examples of process forconstructing thin film transistors on the glass substrate with use ofthe two step halftone exposure method in the twenty first embodiment ofthe present invention. In this example, the two step halftone exposuremethod of the present invention is used in constructing the scanningline 15 and the common electrodes 49 within the pixel 49 at the sametime, and the video signal line 51 and the liquid crystal driveelectrode 53 at the same time.

In the example of FIGS. 27A-27F, a three-layer metal structure isutilized for the scanning line 15 which is created through the processof FIGS. 8A-8E. In the example of FIGS. 28A-28F, a two-layer metalstructure is utilized for the scanning line 15 which is created throughthe process of FIGS. 7A-7E. Both examples of FIGS. 27A-27F and 28A-28Futilize the two-step halftone exposure method in which the commonelectrode 49 within the pixel is structured with a single-layer of thinfilm.

When using the two-step halftone exposure method for forming thescanning line, alignment marks must be formed in the glass substrate inadvance as shown in FIG. 11 by the laser beam device such as shown inFIGS. 9 and 10. Both examples of FIGS. 27A-27F and 28A-28F utilize thehalftone exposure to perform the processes of separating the siliconelements (silicon island forming process) from the semiconductor layerand constructing the terminal portion of contact holes at the same time.

In FIGS. 27A-27F and 28A-28F, a numeral 8 denotes an area where thephotoresist is completely removed after development, a numeral 9 denotesa gate insulation film, a numeral 10 denotes a thin film semiconductorlayer (non-doped layer), a numeral 11 denotes a thin film semiconductorlayer (doped layer, i.e., ohmic contact layer), a numeral 15 denotes ascanning line, a numeral 20 denotes an area of the photoresist which isnot exposed by the UV light, and a numeral 22 denotes an area of thephotoresist which is incompletely exposed (halftone exposure), a numeral49 denotes a common electrode within the pixel, a numeral 50 denotes ascanning line terminal, a numeral 51 denotes a video signal line, anumeral 52 denotes a barrier metal, a numeral 53 denotes a liquidcrystal drive electrode, a numeral 54 denotes a scanning line terminaldrive circuit contact electrode, and a numeral 55 denotes a passivationfilm.

In the example of FIGS. 27A-27F, the scanning line 15, the scanning lineterminal 50 and the common electrode 49 within the pixel have beenformed through the process shown in FIGS. 8A-8E. In the example of FIGS.28A-28F, the scanning line 15, the scanning line terminal 50 and thecommon electrode 49 within the pixel have been formed through theprocess shown in FIGS. 7A-7E. Then, in the both examples of FIGS.27A-27F and 28A-28F, by the same procedures, the silicon elements areseparated and the contact holes are created as follows:

First, as shown in FIGS. 27A and 28A, the gate insulation film 9, thethin film semiconductor layer (non-doped layer) 10, and thin filmsemiconductor layer (ohmic contact layer) 11 are consecutively depositedwith use of a plasma CVD device. After coating the positive photoresistwith a thickness of 2-3 micrometers, the halftone exposure process isconducted on the positive photoresist. Thus, the thicker area 20 and thethinner area 22 of the positive photoresist are created, while thephotoresist is removed at an area over the scanning line terminal 50.

In FIGS. 27B and 28B, contact holes for the scanning line terminals 50are created through, for example, a dry etching process. Then, thethinner area 22 of the photoresist formed through the halftone exposureis removed by the ashing process so that the positive photoresistremains at an area where the thin film transistor will be formed. InFIGS. 27C and 28C, through the dry etching process, the semiconductorlayers are removed except for the areas where the thin film transistorswill be formed. In FIGS. 27D-27F and 28D-28F, the video signal lines 51,the scanning line drive circuit connection electrode 54 and the liquidcrystal drive electrode 53 are created by using the process shown inFIGS. 7A-7E or FIGS. 8A-8E.

As has been described above, in the process shown in FIGS. 27A-27F and28A-28F, with use of the two-step exposure method of the presentinvention, the liquid crystal drive electrode 53 is made of a singlelayer of thin film. As in the present invention, since each of thecommon electrode 49 within the pixel and the liquid crystal driveelectrode 53 is made of a thin film using the two-step halftone exposuremethod in the production process of the scanning line and the videosignal line, smooth movement of the tips of the hairs of the rubbingcloth can be achieved in the alignment treatment, which is able toprevent occurrence of alignment defects.

When the separation of the silicon elements of the thin film transistorsand the construction of the terminal portion of the contact holes areperformed using the halftone exposure method as noted above,electrostatic protection circuits such as shown in FIGS. 21-26 must becreated at the same time. FIGS. 21 and 22 show examples of circuitstructure in the static electricity protection circuit, and FIGS. 23-26show examples of pattern structure for establishing the staticelectricity protection circuits of FIGS. 21 and 22 on the substrate. InFIGS. 21-26, a numeral 14 denotes a video signal line, a numeral 15denotes a scanning line, a numeral 16 denotes a common electrode forelectrostatic protection, a numeral 17 denotes a thin film semiconductorlayer, a numeral 18 denotes a contact hole for creating a thin filmtransistor circuit static electricity protection.

As shown in FIGS. 23, 24, 25 and 26, it is possible to maximize the sizeof the contact holes 18 by positioning them together. In this case, alocal exposure device such as shown in FIGS. 12 and 13 using either anultraviolet laser beam or an ultraviolet LED can be used to locallyexpose the portions of the contact holes. In FIG. 12, a numeral 25denotes an fθ lens, a numeral 29 denotes a laser light source, a numeral30 denotes a beam formatter, a numeral 31 denotes a galvanomirror, anumeral 32 denotes a laser beam, a numeral 33 denotes a mark patternformed within the glass substrate, a numeral 34 denotes an ultrasonicpolarizer, a numeral 35 denotes a UV laser source, a numeral 36 denotesa UV laser light, a numeral 38 denotes the glass substrate for TFTarray, and a numeral 39 denotes a positive photoresist layer.

FIGS. 6A-6C show the first and second exposure steps using the localexposure device. In the example of FIGS. 6A-6C, the second exposure stepis performed without using a photomask but using the fθ lens for locallyexposing a part of the glass substrate. As noted above, the fθ lens isable to focus on a relatively large area on the same flat surface of thesubstrate.

FIGS. 29 and 30 show the plan views of the halftone scan exposure devicehaving a built-in local exposure device of the present invention. InFIGS. 29 and 30, a numeral 40 denotes a micro-mirror array device, anumeral 44 denotes a multi-lens projection module, a numeral 45 denotesa photomask, a numeral 46 denotes an X-Y stage, a numeral 47 denotes aUV source, and a numeral 56 denotes an ultraviolet laser scan exposuredevice. The halftone exposure process and the local exposure process canbe conducted at the same time with use of only one device of either FIG.29 or FIG. 30 and the ordinary photomask. Thus, the productionefficiency can be improved significantly.

FIG. 31 shows the plan view of the transverse electric field type activematrix substrate created with use of the halftone exposure method of thepresent invention. In FIG. 31, a numeral 57 denotes a terminal of thevideo signal line, a numeral 58 denotes a terminal of the commonelectrode surrounding the pixel, a numeral 59 denotes a staticelectricity protection circuit, a numeral 60 denotes a passivation film,and a numeral 61 denotes a contact hole created through the local UVexposure noted above. The contact holes 61 constructed through the localultraviolet ray exposure are positioned together in a line.

FIG. 4 is a flow chart summarizing the process for producing the TFTarray on the substrate using the ordinary photomasks through thetwo-step halftone exposure method of the present invention. The basicprocess of the two-step halftone exposure is shown in FIGS. 5 and 6which uses two or more ordinary photomasks. In the process of FIG. 4,the photomasking process is repeated four times each including the firstand second halftone exposure. First, alignment marks are formed in theglass substrate by a laser beam at step S21. In the first and secondhalftone exposure in step S22, the gate electrodes for thin filmtransistors and the common electrodes are formed at the same time. Then,at step S23, through the first and second halftone exposure, the thinfilm transistors are separated from the semiconductor layer and thecontact holes are created. In step S24, the source and drain electrodesand the liquid crystal drive electrodes are formed at the same timethrough the first and second halftone exposure. Lastly, at step S25,gate terminals and data terminals are formed.

FIG. 124 is a flow chart summarizing the process for producing the TFTarray on the substrate using the ordinary photomasks through thetwo-step halftone exposure method of the present invention. The basicprocess of the two-step halftone exposure is shown in FIGS. 5 and 6which uses two or more ordinary photomasks. In the process of FIG. 124,the photomasking process is repeated three times each including thefirst and second halftone exposure. First, alignment marks are formed inthe glass substrate by a laser beam at step S81. Through the first andsecond halftone exposure, in step S82, the gate electrodes for thin filmtransistors and the common electrodes are formed at the same time. Then,at step S83, through the first and second halftone exposure, the thinfilm transistors are separated from the semiconductor layer and thecontact holes are created. In step S84, the source and drain electrodesof the thin film transistors and the liquid crystal drive electrodes areformed at the same time through the first and second halftone exposure.During this process, a leveling film is applied to the surface of thesubstrate for flattening the surface. For example, after a back channelB2H6 plasma doping treatment, the leveling film is formed by an ink jetprinting method or a partial P—SiNx protection film is formed through amasking method using a shadow frame.

Preferred Embodiment 22

FIGS. 114A-114C and FIGS. 130A-130C are cross sectional views showingexamples of processes in which the steps of flattening (leveling orplanarizing) the substrate and forming the photolithography spacers areconducted with use of both the ordinary photomask exposure and thehalftone back surface exposure in the twenty second embodiment of thepresent invention. In this example, negative photoresist is used. In theexample of FIGS. 114A-114C and FIGS. 130A-130C, a numeral 55 denotes apassivation film, a numeral 71 denotes a TFT array alignment film, anumeral 87 denotes a negative photoresist layer for halftone exposure, anumeral 89 denotes a photolithography spacer, a numeral 91 denotes a UVlight from the back surface of the substrate, a numeral 92 denotes thenegative photoresist remained after the back surface exposure and thedevelopment.

First, the negative photoresist 87 is applied on the passivation film 55for the thickness of the liquid crystal cell gap as shown in FIGS. 114Aand 130A. Next, as shown in the upper part of FIGS. 114B and 130B, thecomplete exposure is done with an ordinary photomask at the areas wherethe photolithography spacers are to be constructed. Then, as shown inthe lower part of FIGS. 114B and 130B, with use of the scanning typeback surface exposure device such as shown in FIGS. 131, 132, 133 and134, the negative photoresist 87 is exposed by the ultraviolet rays 91from the back surface of the active matrix substrate to expose enoughlight for a thickness sufficient to flatten the irregularity of thesubstrate. After the back surface exposure, flattening of the substrate(TFT alignment film 71) and construction of the photo spacer 89 areeffectively done at the same time as shown in FIGS. 114C and 130C.

FIG. 129 is a flow chart summarizing the process of producing the activematrix substrate including the steps for flattening (leveling) thesubstrate and forming the photolithography spacers by using the ordinaryphotomask exposure and the halftone back surface exposure in the twentysecond embodiment. In step S131, the gate electrodes for thin filmtransistors and the common electrodes are formed at the same time. Then,at step S132, silicon elements for the thin film transistors areseparated from the semiconductor layer. At step S133, the source anddrain electrodes of the thin film transistors and the liquid crystaldrive electrodes are formed at the same time. Then, the contact holesare formed at step S134. Next, the static electricity protectioncircuit, gate terminal and data terminal are formed in step S135.Lastly, at step S136, the creation of photolithography spacers and theleveling of the substrate surface are conducted by first conducting thehalftone back exposure for flattening the substrate surface and thenconducting the complete exposure for forming the photolithographyspacers.

FIGS. 131 and 132 shows a scanning type back surface exposure deviceutilized in the twenty second embodiment of the present invention. Inthe example of FIGS. 131 and 132, a numeral 19 denotes a UV light, anumeral 76 denotes a glass substrate for the TFT array, a numeral 87denotes a negative photoresist for halftone exposure, a numeral 102denotes a conveyer roller, a numeral 103 denotes a UV cut cover, and anumeral 104 a silica glass fiber. The glass substrate 76 is movedhorizontally on the roller 102 so that the large substrate can beexposed by a relatively small exposure device. The silica glass fibers104 are bundled together and positioned next to each other to produce aconstant strength of ultraviolet ray. In the example of FIGS. 133 and134, the back surface exposure device includes a plurality ofultraviolet ray LEDs 107 positioned next to each other to produce auniform power level of the ultraviolet rays 19.

FIGS. 135-137 show examples of optical system including a white lightinterferometer and a process using the optical system for preciselymeasuring the height of the photolithography spacers constructed on theactive matrix substrate. FIG. 135 shows an overall system configurationfor producing the active matrix substrate including the halftone backsurface exposure device of the present invention, FIG. 136 is a flowchart showing an overall process of the halftone back surface exposuremethod of the present invention, and FIG. 137 shows an example ofoptical system structure in the white light interferometer used in thepresent invention.

In the flow chart of FIG. 136, at step 141, the negative photoresist iscoated on the glass substrate where the thickness of the negativephotoresist is adjusted based on the measured data regarding the heightof the photolithography spacer and photoresist on the substrate. At step142, the halftone back surface exposure is performed in which the amountof light exposure is adjusted based on the measured data. After thehalftone back surface exposure, the negative photoresist for thephotolithography spacers is completely exposed in step 143. After thedevelopment in step S144, the height of the photolithography spacers aremeasured by, for example, the white light interferometer, the result ofwhich is feedbacked to the photoresist coating and the halftone backsurface exposure through a step S146 for adjusting the photoresistcoating thickness and amount of light for exposure. The above processmay repeated two or more times. The resultant substrate is evaluated atstep 147, and if the result is acceptable, the process moves to a postbake process in step S148.

In the example of FIG. 137, the white light interferometer includes aCCD camera, a white light source, a mirror, and an interferometricobjective lens. The vertical position of the interferometric objectivelens is controlled by a mechanism using, for example, a piezo-electricdevice (PZT) for focusing the white light on the top and bottom of thephotolithography spacer and/or negative photoresist. The voltage usedfor driving the piezo-electric device can be used as the measured dataindicating the height of the photolithography spacer.

As shown in FIGS. 135, 136 and 137, the white light interferometeraccurately measures the thickness of the negative resist layer and theheight of the spacer on the glass substrate. This measurement data fromthe white light interferometer is feedbacked to the coater (slit coaterand spin coater) and the halftone back exposure system to adjust thecoating thickness of the negative photoresist and the amount of lightfor the halftone back surface exposure. Accordingly, the surfaceirregularity of the substrate and the height irregularity of thephotolithography spacers can be minimized.

FIGS. 107A-107D show the processes for performing the flattening(leveling) the substrate surface first then constructing thephotolithography spacers using the scanning type back surface exposuredevice of the present invention. In the example of FIGS. 107A-107D, anumeral 9 denotes a gate insulation film, a numeral 49 denotes a commonelectrode within the pixel, a numeral 51 denotes a video signal line, anumeral 53 denotes a liquid crystal drive electrode, a numeral 55denotes a passivation film, a numeral 71 denotes a TFT array alignmentfilm, a numeral 75 denotes a common electrode for shielding the videosignal line, a numeral 76 denotes a glass substrate for TFT array, anumeral 88 denotes a negative photoresist layer for leveling(flattening) the substrate surface, a numeral 89 denotes aphotolithography spacer, a numeral 91 denotes a UV light, and a numeral92 denotes negative photoresist remained after back surface exposure.

In the example of FIGS. 107A-107D, the negative photoresist 88 isapplied on the passivation film 55 for the thickness of the liquidcrystal cell gap as shown in FIG. 107A. The UV light 91 is applied fromthe back surface of the glass substrate 76 to expose the negativephotoresist 88 by an enough light for a thickness sufficient to flattenthe irregularity of the substrate. After the development, the negativephotoresist 92 is remained on the glass substrate in a flat manner toform a flat surface as shown in FIG. 107B. Then, the negativephotoresist is coated again and the complete exposure is performed withan ordinary photomask at the areas where the photolithography spacersare to be constructed. Thus, the photolithography spacers 89 are createdafter development as shown in FIG. 107C. Lastly, the alignment film 71is formed on the surface of the substrate as shown in FIG. 107D.

Although the photolithography spacers are utilized in the example ofFIGS. 107A-107D, 114A-114C and 130A-130C, the spacer bumps 73 describedabove with respect to the first, second, fifth, sixth and ninthembodiments can also be utilized. When the scanning type back surfaceexposure method is used to perform the flattening process, metalelectrodes that do not allow the light to transmit therethrough must beused for the common electrodes 49 within the pixel and the liquidcrystal drive electrodes 53.

FIG. 105 is a flow chart summarizing the process of producing the activematrix substrate including the steps for flattening (leveling) thesubstrate and forming the photolithography spacers using the ordinaryphotomask exposure method and the halftone back surface exposure in thetwenty second embodiment. In step S41, the gate electrodes of the thinfilm transistors and the common electrodes are formed at the same time.Then, at step S42, the silicon elements for the thin film transistorsare separated from the semiconductor layer, and the contact holes areformed at the same time using the first and second halftone exposure.Then in step S43, the source and drain electrodes of the thin filmtransistors and the liquid crystal drive electrodes are formed at thesame time. During this step, after creating the source and drainelectrodes and the liquid crystal drive electrodes, a leveling film isapplied on the substrate and the surface flattening (leveling) isperformed by the halftone back surface exposure. Lastly, at step S44,the photolithography spacers are created through the complete exposure.

Preferred Embodiment 23

FIG. 125 is a flow chart showing an example of production processesinvolved in the transverse electric field type active matrix substrateaccording to the twenty third embodiment of the present invention. Thereare five photolithography processes. In step S91, the gate electrodes ofthe for thin film transistors and the common electrodes are formed atthe same time. Then, at step S92, silicon elements for the thin filmtransistors are separated from the semiconductor layer, and the contactholes are formed at the same time through the first and second halftoneexposure. In step S93, the source and drain electrodes of the thin filmtransistors and the liquid crystal drive electrodes are formed at thesame. Then, at step S94, the photolithography spacer is formed throughthe complete exposure after the surface flattening (leveling) isconducted through the halftone back surface exposure method. Lastly, atstep S95, contact holes for the gate terminals and data terminals areformed.

In the twenty third embodiment described above, the production processis already significantly shortened by utilizing the processesimplemented in the twenty first embodiment and the twenty secondembodiment. The flattening (leveling) process is performed on thesurface of the substrate, thus, alignment defects will not arise duringthe rubbing alignment treatment. As a result, light leakage during theblack display is minimized, thereby achieving a display with highcontrast.

FIG. 128 is a flow chart summarizing a further example of process forproducing the active matrix substrate including the steps for flattening(leveling) the substrate and forming the photolithography spacers usingthe ordinary photomask exposure and the halftone back surface exposurein the twenty third embodiment. In step S121, the gate electrodes of thethin film transistors and the common electrodes are formed at the sametime. Then, at step S122, silicon elements for the thin film transistorsare separated from the semiconductor layer. At step S123, the contactholes are formed. In step S124, the source and drain electrodes of thethin film transistors and the liquid crystal drive electrodes are formedat the same time. During this process, a leveling film is applied to thesurface of the substrate. For example, after a back channel B2H6 plasmadoping treatment, the leveling film is formed by an ink jet printingmethod or a partial P—SiNx protection film is formed through a maskingmethod using a shadow frame. Lastly, at step S125, the leveling of thesubstrate surface are conducted through the halftone back surfaceexposure, and then, the photolithography spacers are formed through thecomplete exposure.

Preferred Embodiment 24

FIG. 126 is a flow chart showing an example of process involved in theproduction of the transverse electric field type active matrix substrateaccording to the twenty fourth embodiment of the present invention.There are four photolithography steps in this process. In step S101, thegate electrodes of the thin film transistors and the common electrodesare formed at the same time. Then, at step S102, the silicon elementsfor the thin film transistors are separated from the semiconductor layerand the contact holes are formed at the same time through the first andsecond halftone exposure. In step S103, the source and drain electrodesand liquid crystal drive electrodes are formed at the same time. Duringthis process, a leveling film is applied to the surface of thesubstrate. For example, after a back channel B2H6 plasma dopingtreatment, the leveling film is formed by an ink jet printing method ora partial P—SiNx protection film is formed through a masking methodusing a shadow frame. Lastly, at step S104, the flattening process forthe substrate surface are conducted through the halftone back surfaceexposure, and then, the photolithography spacers are formed through thecomplete exposure. The overall production process is significantlyshortened by utilizing the processes in the twenty first embodiment andthe twenty second embodiment described above.

In the twenty fourth embodiment, although the P—SiNx passivation layeris applied using the P-CVD device on the entire surface of the substratein the twenty third embodiment, the process for opening the contactholes for terminals of the scanning lines (gate electrodes) and thevideo signal line (data electrodes) is eliminated by partially applyingthe P—SiNx passivation layer using a partial layer construction methodusing a shadow frame or by partially applying an organic passivationlayer (BCB for example) using an application device such as an ink jetprinter. Similar to the foregoing embodiments, since the substratesurface undergoes a leveling process, alignment defects will not occurduring the rubbing treatment.

Preferred Embodiment 25

FIG. 127 is a flow chart showing an example of process involved in theproduction of transverse electric field type active matrix substrateaccording to the twenty fifth embodiment of the present invention. Thereare three photolithography processes. In step S111, the gate electrodesof the thin film transistors and the common electrodes are formed at thesame time through, for example, a masking deposition process using ashadow frame for a structure of P—SiNx\a-Si i\n+a-Si. Then, at stepS112, the silicon elements for the thin film transistors are separatedfrom the semiconductor layer and the source and drain electrodes of thethin film transistors are formed at the same time through the first andsecond halftone exposure. During this process, a leveling film isapplied to the surface of the substrate. For example, after a backchannel B2H6 plasma doping treatment, the leveling film is formed by anink jet printing method or a partial P—SiNx protection film is formedthrough a masking method using a shadow frame. Lastly, at step S113, theleveling of the substrate surface are conducted through the halftoneback surface exposure, and then, the photolithography spacers are formedthrough the complete exposure.

By utilizing the processes in the seventeenth embodiment and the twentysecond embodiment, the time required for the overall production processis significantly shortened. This embodiment can eliminate the processfor opening the contact holes for terminals of the scanning lines (gateelectrodes) and the video signal line (data electrodes) by partiallyapplying the P—SiNx passivation layer using a partial layer constructionmethod utilizing a shadow frame or by partially applying an organicpassivation layer (BCB for example) using an application device such asan ink jet printer. Similar to the foregoing embodiments, since thesubstrate surface undergoes a flattening process, alignment defects willnot occur during the rubbing treatment.

[Effect of the Present Invention]

As has been described above, according to the present invention, byutilizing the halftone shift exposure method using an ordinaryphotomask, or by utilizing the halftone mixed exposure method which is acombination of the halftone exposure using the ordinary photomask andthe local additional exposure, the transverse electric field type liquidcrystal display device can be produced with low cost and high productionyield.

By utilizing the halftone back surface scanning exposure method of thepresent invention and by constructing the photolithography spacers inone negative photoresist process, low production cost, high displayquality without alignment defects, and high contrast can be achieved.

By adapting the spacer bump structure of the present invention, thetransverse electric field type liquid crystal display system with highaperture ratio and low production cost can be realized. By constructingthe upper layer shielding common electrodes, the common electrodeswithin the pixel, and the liquid crystal drive electrodes by the sameconductive material on the same layer, it is possible to produce a highquality display device with minimized residual image, high apertureratio, and with uniform and deep black level display. By implementingthe present invention, an ultra large screen transverse electric fieldtype liquid crystal display television with low cost and high contrastcan be realized.

Although the invention is described herein with reference to thepreferred embodiments, one skilled in the art will readily appreciatethat various modifications and variations may be made without departingfrom the spirit and scope of the present invention. Such modificationsand variations are considered to be within the purview and scope of theappended claims and their equivalents.

1. A liquid crystal display device having a transverse electric fieldtype active matrix substrate, comprising: a thin and long bump made ofinsulation material placed on a video signal line formed on the activematrix substrate in a manner to cover the video signal line, the bumphaving a taper angle of less than 30 degrees relative to a horizontalsurface of the active matrix substrate at each edge thereof formedthrough a halftone process; and a common electrode formed along thevideo signal line in a manner to cover the thin and long insulation bumpand the video signal line; thereby shielding an electric field generatedby the video signal line by the common electrode; and wherein the thinand long insulation bump formed in the manner to cover the video signalline has a cross sectional shape of a circular, semi-circular,hyperbolic, or parabolic to form a rounded curve thereon.
 2. A liquidcrystal display device as defined in claim 1, wherein the thin and longinsulation bump formed in the manner to cover the video signal linefunctions as a spacer to define a liquid crystal cell gap whenassembling the liquid crystal cells.
 3. A liquid crystal display deviceas defined in claim 1, wherein the common electrode for shielding thevideo signal line is made of a thin-film transparent conductive materialthat allows light to transmit in a degree greater than 20% such astitanium metal compound including titanium nitride (TiNx), titaniumoxide nitride (TiOxNy), titanium silicide nitride (TiSixNy), andtitanium silicide (TiSix), or a metal oxide transparent conductivematerial such as indium oxide (In2O3) or zinc oxide (ZnO).
 4. A liquidcrystal display device as defined in claim 1, wherein the thin and longinsulation bump formed in the manner to cover the video signal line isdiscontinued around an area at which a video signal line and a scanningline intersect with one another.
 5. A liquid crystal display device asdefined in claim 1, wherein the common electrodes are provided in anupper layer and a lower layer on the active matrix substrate through agate insulating film and a passivation film therebetween in a manner tosandwich the video signal line in up/down directions and right/leftdirections, wherein the common electrode on the lower layer is made of ametal electrode which prohibits the light to pass there through whereasthe common electrode in the upper layer is a transparent electrode thatallows the light to pass there through, and wherein the common electrodeat the upper layer has an electrode width wider than that of the commonelectrode in the lower layer and is projected towards a side of a liquidcrystal drive electrode.
 6. A liquid crystal display device as definedin claim 1, wherein the video signal line, the thin and long insulationbump formed in the manner to cover the video signal line, and the commonelectrode formed along the video signal line for shielding the videosignal line are aligned in a manner of straight line, wherein a liquidcrystal drive electrode within a pixel and a common electrode within thepixel are bent within the pixel at least once at an angle within a rangebetween 0-30 degrees (except 0 degree) relative to an alignmentdirection of a liquid crystal molecule.
 7. A liquid crystal displaydevice as defined in claim 1, wherein the video signal line and the thinand long insulation bump formed in the manner to cover the video signalline are aligned in a manner of straight line, wherein the commonelectrode formed along the video signal line for shielding the videosignal line, a liquid crystal drive electrode within a pixel, and acommon electrode within the pixel are bent within the pixel at leastonce at an angle within a range between 0-30 degrees (except 0 degree)relative to an alignment direction of a liquid crystal molecule.
 8. Aliquid crystal display device as defined in claim 1, wherein the videosignal line, the thin and long insulation bump formed in the manner tocover the video signal line, the common electrode formed along the videosignal line for shielding the video signal line, and a common electrodewithin a pixel are aligned in a manner of straight line, wherein aliquid crystal drive electrode within the pixel is bent within the pixelat least once at an angle within a range between 0-30 degrees (except 0degree) relative to an alignment direction of a liquid crystal molecule.9. A liquid crystal display device as defined in claim 1, wherein thevideo signal line, the thin and long insulation bump formed in themanner to cover the video signal line, the common electrode formed alongthe video signal line for shielding the video signal line, a commonelectrode within a pixel, and a liquid crystal drive electrode withinthe pixel are bent within the pixel at least once at an angle within arange between 0-30 degrees (except 0 degree) relative to an alignmentdirection of the liquid crystal molecule.
 10. A liquid crystal displaydevice as defined in claim 1, wherein the video signal line, the thinand long insulation bump formed in the manner to cover the video signalline, the common electrode formed along the video signal line forshielding the video signal line, a common electrode within a pixel, anda liquid crystal drive electrode within the pixel are bent within thepixel at least once at an angle within a range between 0-30 degrees(except 0 degree) relative to an alignment direction of the liquidcrystal molecule, and wherein a color filter layer and a light shieldingfilm (black mask) are bent within the pixel at least once, in a mannersimilar to the video signal line, at an angle within a range between0-30 degrees (except 0 degree) relative to an alignment direction of aliquid crystal molecule.
 11. A liquid crystal display device as definedin claim 1, wherein the video signal line, the thin and long insulationbump formed in the manner to cover the video signal line, and the commonelectrode formed along the video signal line for shielding the videosignal line are aligned in a manner of straight line, wherein a liquidcrystal drive electrode within a pixel and a common electrode within thepixel are bent within the pixel at least once at an angle within a rangebetween 60-120 degrees (except 90 degrees) relative to an alignmentdirection of a liquid crystal molecule.
 12. A liquid crystal displaydevice as defined in claim 1, wherein the video signal line and the thinand long insulation bump formed in the manner to cover the video signalline are aligned in a manner of straight line, wherein the commonelectrode formed along the video signal line for shielding the videosignal line, a liquid crystal drive electrode within a pixel, and acommon electrode within the pixel are bent within the pixel at leastonce at an angle within a range between 60-120 degrees (except 90degrees) relative to an alignment direction of a liquid crystalmolecule.
 13. A liquid crystal display device as defined in claim 1,wherein the video signal line, the thin and long insulation bump formedin the manner to cover the video signal line, the common electrodeformed along the video signal line for shielding the video signal line,and a common electrode within a pixel are aligned in a manner ofstraight line, wherein only a liquid crystal drive electrode within thepixel is bent within the pixel at least once at an angle within a rangebetween 60-120 degrees (except 90 degrees) relative to an alignmentdirection of a liquid crystal molecule.
 14. A liquid crystal displaydevice as defined in claim 1, wherein the video signal line, the thinand long insulation bump formed in the manner to cover the video signalline, the common electrode formed along the video signal line forshielding the video signal line, a common electrode within a pixel, anda liquid crystal drive electrode within the pixel are bent within thepixel at least once at an angle within a range between 60-120 degrees(except 90 degrees) relative to an alignment direction of the liquidcrystal molecule.
 15. A liquid crystal display device as defined inclaim 1, wherein the video signal line, the thin and long insulationbump formed in the manner to cover the video signal line, the commonelectrode formed along the video signal line for shielding the videosignal line, a common electrode within a pixel, and a liquid crystaldrive electrode within the pixel are bent within the pixel at least onceat an angle within a range between 60-120 degrees (except 90 degrees)relative to an alignment direction of a liquid crystal molecule, andwherein a color filter layer and a light shielding film (black mask) arebent within the pixel at least once, in a manner similar to the videosignal line, at an angle within a range between 60-120 degrees (except90 degrees) relative to an alignment direction of the liquid crystalmolecule.
 16. A liquid crystal display device as defined in claim 1,wherein the thin and long insulation bump formed along the video signalline to cover the video signal line has a dielectric constant of lessthan 3.3, and a height h1 is in a range between 1.5 micrometers and 5.0micrometers, and wherein a distance L1 between an edge of the videosignal line and an edge of the insulation bump is in a range between 3.0micrometers and 6.0 micrometers.
 17. A liquid crystal display device asdefined in claim 1, wherein a distance L2 between an edge of theinsulation bump covering the video signal line and an edge of theshielding common electrode covering the insulation bump is in a rangebetween 0.5 micrometers and 10.0 micrometers.
 18. A liquid crystaldisplay device as defined in claim 1, wherein monomer or oligomer usedas a material for fabricating the insulation bump covering the videosignal line has at least one benzo-cyclobutene structure or itsdielectric form or has at least one fluorene skeleton or its dielectricform.
 19. A liquid crystal display device as defined in claim 1,wherein, when forming the thin and long insulation bump covering thevideo signal line, at least one barrier bump spacer in a closed loopstructure is formed at the same time for preventing breakage of a mainseal due to an atmospheric pressure or a pressure from liquid crystalsat a location identical to an area on which the main seal of the liquidcrystal cell that surrounds an entire effective pixel area is formed.20. A liquid crystal display device as defined in claim 1, wherein thecommon electrodes formed along the thin and long insulation bumps in themanner to cover the video signal lines for shielding are connected witheach other throughout an entire effective pixel display area and are setto an electric potential close to a center voltage of a video signalvoltage.
 21. A liquid crystal display device as defined in claim 1,wherein the spacer bumps have a characteristic of elastically and thespacer bumps evenly deform in a range between 0.1 micrometers and 0.5micrometers in response to an atmospheric pressure during a process ofconstructing a liquid crystal cell by superposing an active matrixsubstrate and a color filter substrate with one another under a vacuumatmosphere.